Southern  Branch 
of  the 

University  of  California 

Los  Angeles 

Form  L  1 

QL 

81 

T38 


This  book  is  DUE  on  the  last  date  stamped  belo- 


JAK 


SOUTHERN 
UN!V,      . 


'- 


LOS   A 


THE  HAUNTS  OF  LIFE 


SALMON?  ASCENDING  A  FALL. 


frontispiece} 


THE 
HAUNTS  OF  LIFE 


BY 

PROF.  J.  ARTHUR  THOMSON,  M.A.,  LL.D. 

Author  of  "The  Wonder  of  Life,"    "The  Biology  of  the 

Seasons,"   "Secrets  of  Animal  Life,"    "Darwinism 

and  Human  Life,"   etc. 


NEW  YORK 

HARCOURT,  BRACE  AND  COMPANY 

w  o 


78301 


COPYRIGHT,    1922,   BY 
HARCOURT,   BRACE  AND  COMPANY,   INC. 


IN    THE    U.  S.  A.  BY 
4    a    BOOEN    COMPANY 
tHWAY.    N.    J. 


THIS   LITTLE    BOOK 
IS     DEDICATED     GRATEFULLY 
TO   A   VETERAN    NATURALIST 

EMERITUS  PROFESSOR  W.  C.  M'INTOSH 

M.D.,   LL.D.,  F.R.S. 

WHO    HAS  DEVOTED   HIS   LIFE 
TO  THE    STUDY   OF   ANIMALS  IN   THEIR   HAUNTS 


PUBLISHERS'   NOTE 

the  illustrations  in  this  book  twelve 
plates  are  by  Mr.  William  Smith;  the 
remainder  are  by  Miss  Alice  M.  Davidson. 


PREFACE 

THIS  simple  book  consists  of  six  lectures 
which  I  had  the  honour  and  pleasure  of 
giving  at  the  Royal  Institution  in  the  Christ- 
mas holidays,  1920-1921.    The  aim  of  these 
lectures  was  mainly  to  help  my  very  alert 
0     audience  to  form  vivid  pictures  of  the  great 
^    haunts  of  animal  life,  and  to  get  glimpses  of 
X  the  subtle  ways  in  which  living  creatures  solve 
the  problems  of  particular  places.     I  have 
kept  in  the  printed  pages  as  closely  as  I  could 
to  what  I  said  at  the  time,  hoping  to  secure 
*J^    the  virtue  of  simplicity.    I  think  it  would  be 
very  ungracious  if  I  did  not  use  the  oppor- 
tunity of  this  preface   to   thank   Sir  James 
Dewar,  LL.D.,  D.Sc.,  F.R.S.,  for  the  great 
kindness  that  he  showed  me  when  I  was  for 
a  delightful  fortnight  in  the  service  of  the 
Royal  Institution.  TAT 


vii 


CONTENTS 

CHAPTER   I 
THE  SCHOOL  OF  THE  SHORE 

The  Shore  of  the  Sea — In  Deeper  Waters  near 
Shore — A  Representative  Population — A  Dif- 
ficult Place  to  Live  in — The  Struggle  of  the 
Shore — The  Circulation  of  Matter — Canni- 
balism in  the  Cradle — Shore  Seaweeds — Food- 
getting  on  the  Shore — The  Story  of  the 
Angler — The  Star-fish  and  Sea-urchin  Fight — 
Shifts  for  a  Living  on  the  Shore — Masking — 
A  Limb  for  a  Life — Colour  Camouflage — 
Love  on  the  Shore — The  Story  of  Palolo — A 
Great  School i 

CHAPTER   II 
THE  OPEN  SEA 

Contrast  between  Shore  and  Open  Sea — The  Float- 
ing Sea-Meadows — The  Animals  of  the  Open 
Sea — Sea-deserts — Swimmers  and  Drifters — 
The  Whale  as  a  Great  Bundle  of  Fitnesses — 
The  Story  of  the  Storm  Petrel — Open-Sea  In- 
sects— Turtles — Sea-Snakes  and  Sea-Serpents 
— Fitnesses  of  Open-Sea  Drifters — The  Story 
of  the  Floating  Barnacle — Hunger  and  Love 
in  the  Open  Sea — The  Open  Sea  as  a  Nursery  64 


x  CONTENTS 

CHAPTER   III 
THE  GREAT  DEEPS 

TAGE 

The  Challenger  Expedition — The  Deep  Deep  Sea 
— Great  Pressure — Very  Cold — Very  Dark — 
Very  Calm  and  Silent — Monotony — No  Depth 
Limit  to  Life — No  Plants  in  the  Deep  Sea — 
No  Rottenness — A  Representative  Fauna — 
Fitnesses  of  Deep-Sea  Animals — Puzzle  of 
Phosphorescence — Big  Eyes  and  Little  Eyes — 
Origin  of  Deep-Sea  Animals — Hunger  and 
Love  in  the  Deep  Sea — Retrospect  .  .  .  104 


CHAPTER    IV 
THE  FRESH  WATERS 

Variety  of  the  Fresh  Waters — Similar  Animals  in 
Widely  Separated  Places — From  Salt  Water 
to  Fresh — Origin  of  Fresh-Water  Animals — 
Circulation  of  Matter  in  the  Fresh  Waters — 
The  Web  of  Life  in  the  Fresh  Waters— The 
Danger  of  Drought — The  Danger  of  Frost — 
The  Danger  of  Flood — Parental  Care  among 
Fresh-Water  Animals— The  Story  of  the  Eel 
— The  Story  of  the  Salmon — The  Story  of 
the  Lamprey — Water  Insects — The  Story  of 
the  Fresh- Water  Spider 136 

CHAPTER   V 
THE  CONQUEST  OF  THE  DRY  LAND 

Tell-tale  Evidences  of  Marine  Ancestry — Origin  of 
Land  Plants — The  Three  Great  Invasions  of 
the  Dry  Land — New  Ways  of  Breathing — 


CONTENTS  xi 

PAGE 

Changes  in  Movements — New  Ways  of  Look- 
ing after  the  Young — New  Kinds  of  Protec- 
tion— Betwixt-and-Between  Animals — Haunts 
within  Haunts — Beneath  the  Ground — Cave 
Animals — Arboreal  Life 185 


CHAPTER   VI 
THE  MASTERY  OF  THE  AIR 

What  Getting  into  the  Air  meant — The  Flight  of 
Insects — Why  are  there  so  many  Insects? — 
The  Flying  Dragons — The  Flight  of  Birds — 
Different  Kinds  of  Flying  in  Birds — Migration 
the  Climax— The  Fourth  Solution  of  Flight- 
Fitnesses  of  Birds  and  Bats — Attempts  at 
Flight — Gossamer  Spiders  .  .  .  .231 

Index 270 


LIST   OF   ILLUSTRATIONS 

FIG.  PAGE 

1.  KING-CRAB 14 

2.  ACORN-SHELLS  OR  ROCK-BARNACLES      .       .  40 

3.  SKATE-SUCKER 57 

4.  RIGHT  WHALE 78 

5.  SEA-SKIMMER 86 

6.  JELLY-FISH 91 

7.  LlFE-HlSTORY    OF    THE   ANGLER          ...          93 

8.  OPEN-SEA  WATER-FLEA 95 

9.  CLUSTER  OF  BARNACLES 97 

10.  FLOATING  BARNACLES 98 

11.  FEATHER-STARS  OR  SEA-LILIES  .       .       .       .121 

12.  SEA-PENS  AND  UMBELLULAS  ....     127 

13.  CIRCULATION  OF  MATTER       .       .       .        .146 

14.  LlFE-HlSTORY    OF    GNAT 152 

15.  QUEENSLAND  Muo-FiSH 155 

1 6.  SPOTTED  SALAMANDER 160 

17.  GARDEN  SPIDER 180 

1 8.  FEMALE  FRESH- WATER  SPIDER       .       .       .182 

xiii 


xiv  LIST  OF  ILLUSTRATIONS 

PIG.  PAGE 

19.  PERIPATUS 194 

20.  CENTIPEDE 195 

21.  GREEN  LIZARD 201 

22.  JERBOA 206 

23.  AUSTRALIAN  COLLARED  LIZARD      .       .       .  208 

24.  AUSTRALIAN  DUCKMOLE 211 

25.  SPINY  ANT-EATER 218 

26.  PERIOPHTHALMUS      .  222 

27.  ROBBER-CRAB 224 

28.  DIAGRAM  OF  SOME  BURROWERS        .       .       .  227 

29.  WINGS 252 

30.  FLYING  FISHES  .......  259 

31.  FLYING  TREE-TOAD 261 

32.  LITTLE  FLYING  DRAGON  OF  MALAY      .       .  262 
33-  GOSSAMER  SPIDERS 268 


LIST  OF  PLATES 

SALMON  ASCENDING  A  FALL       .       Frontispiece 

PLATE  FACING  PAGE 

I.    CROWDED  GROUP  OF  GUILLEMOTS  ON  A 

STACK  OF  ROCK 7 

II.   TERNS  OR  SEA-SWALLOWS  FLYING  ON  THE 

SHORE n 

III.  FOUR  OPEN-SEA  ANIMALS        ...  64 

IV.  GLAUCOUS  GULL  AT  LERWICK         .       .  67 
V.    OPEN-SEA  ANIMALS 73 

VI.  THE  STORM  PETREL  IN  THE  OPEN  SEA  .       84 

VII.  THE  FLOOR  OF  THE  DEEP  SEA  .       .       .     105 

VIII.  DEEP  SEA  NEAR  SHORE      .       .       .       .115 

IX.  A  FRESH-WATER  POOL      .       .       .       .140 

X.  A  FRESH- WATER  POOL      .       .       .       .158 

XI.  SNOW-COVERED  MOORLAND  IN  WINTER  .     220 

XII.  A  CAVE  IN  DALMATIA       ....     228 

XIII.  DIAGRAM  OF  FIVE  HAUNTS  OF  LIFE        .     231 

XIV.  BATS  FLYING   IN  THE  TWILIGHT         .  .       254 

XV.   FLYING  DRAGONS,  DRACO  VOLANS,  OF  THE 

FAR  EAST 260 

XVI.  GULLS  IN  FLIGHT 266 


THE   HAUNTS  OF  LIFE 

CHAPTER  I 
THE  SCHOOL  OF  THE  SHORE 

The  Shore  of  the  Sea — In  Deeper  Waters  near  Shore — A 
Representative  Population — A  Difficult  Place  to  Live  in — 
The  Struggle  of  the  Shore— The  Circulation  of  Matter- 
Cannibalism  in  the  Cradle — Shore  Seaweeds — Food- 
getting  on  the  Shore — The  Story  of  the  Angler — The 
Star-fish  and  Sea-urchin  Fight — Shifts  for  a  Living  on 
the  Shore — Masking — A  Limb  for  a  Life — Colour  Camou- 
flage— Love  on  the  Shore — The  Story  of  Palolo — A  Great 
School. 

IT  is  interesting  to  watch  a  big  river  rising 
slowly  in  flood.  The  water  overtops  the 
banks  and  spreads  foot  by  foot  everywhere, 
rilling  every  hollow,  forgetting  no  corner.  So 
is  it  with  living  creatures;  they  spread  over 
all  the  earth.  Life  is  like  a  river  that  is  always 
overflowing  its  banks.  There  are  no  fishes  in 
the  Great  Salt  Lake  of  Utah,  there  are  no 
birds  swimming  on  its  surface,  yet  there  are 
brine-shrimps  and  two  or  three  more  living 


2  THE  HAUNTS  OF  LIFE 

creatures  tenanting  its  dense  waters.  Little 
fresh-water  snails  may  be  seen  creeping  on  the 
stones  close  to  the  brink  of  the  Niagara  Falls. 
An  army  of  a  million  tiny  wingless  insects  has 
been  observed  crossing  the  Mer  de  Glace  near 
Chamonix.  There  are  insects  that  run  about 
on  the  surface  of  the  Open  Sea.  There  are 
many  animals  that  find  a  home  in  coal-pits. 
It  seems  as  if  there  are  no  corners  which  liv- 
ing creatures  have  not  explored,  from  the 
great  abysses  of  the  Deep  Sea,  perhaps  six 
miles  below  the  surface,  to  near  the  summits 
of  the  Alps,  from  the  floating  iceberg  in  the 
North  to  beneath  ten  feet  of  ice  on  the  Ant- 
arctic shore.  Perhaps  there  are  always  some 
living  creatures  trying  to  conquer  a  new  king- 
dom. Life  is  a  kind  of  activity,  and  living 
creatures  tend  to  be  restless,  seeking  out  places 
where  they  can  express  themselves  and  assert 
themselves  more  fully. 

Thus  it  has  come  to  pass  that  living  crea- 
tures have  spread  over  all  the  earth,  and  in 
the  waters  under  the  earth,  and  in  more  than 
the  seven  seas.  One  may  almost  say  that  over 
earth  and  sea  life  is  omnipresent.  But  it  is 
very  useful  to  distinguish  Six  GREAT  HAUNTS 
OF  LIFE: 


THE  SCHOOL  OF  THE  SHORE  3 

I.  THE  SHORE  OF  THE  SEA  (Littoral). 
II.  THE  OPEN  SEA  (Pelagic). 

III.  THE  DEPTHS  OF  THE  SEA  (Abyssal). 

IV.  THE  FRESH  WATERS  (Fluviatile,  La- 

custrine, etc.). 

V.  THE  DRY  LAND  (Terrestrial). 
VI.  THE  Am  (Aerial). 

THE  SHORE  OF  THE  SEA 

By  the  shore-haunt  or  littoral  region  natu- 
ralists mean  more  than  is  suggested  in  ordi- 
nary conversation  when  we  speak  of  the  sea- 
shore. For  then  we  mean  the  stretch  between 
tide-marks,  whereas  the  naturalist's  shore- 
haunt  is  the  whole  of  the  comparatively 
shallow,  well-lighted,  seaweed-growing  area 
round  the  margin  of  a  continent,  or  of  an 
island  that  was  once  part  of  a  continent. 
There  are  places  where  there  is  practically  no 
shore;  for  instance  round  an  oceanic  island 
that  has  been  formed  by  corals  growing  on  the 
shoulders  of  a  submarine  volcano.  In  such  a 
place  a  stone  thrown  out  from  the  land  will 
drop — kerblunkity  blink — into  really  deep 
water.  And  there  are  other  places  where  the 
shore  goes  out  and  out  for  many  miles;  for 


4  THE  HAUNTS  OF  LIFE 

instance,  where  a  fringing  coral-reef  extends 
far  out  to  sea.  The  naturalist's  shore-haunt 
is  the  whole  of  the  seaweed-growing  area,  and 
we  call  it  shore,  although  the  water  may  be 
deep  enough  to  float  a  navy. 

The  shore-haunt  is  not  very  large  compared 
with  other  haunts.  It  occupies  about  nine  mil- 
lion square  miles,  but  that  is  only  between  six 
and  seven  per  cent,  of  the  sea-covered  surface 
of  the  globe.  It  is  a  very  long  area,  going  in 
and  out,  by  bay  and  creek,  by  firth  and  fiord, 
for  about  150,000  miles.  And  it  is  a  region  of 
great  diversity,  differing  from  place  to  place 
according  to  the  geological  character  of  the 
shore,  according  to  the  mineral  materials  that 
the  streams  bring  down  from  the  land,  and 
according  to  the  jetsam  that  is  thrown  up 
from  the  sea.  In  some  places  the  whole  of  the 
shore  between  tide-marks  is  covered  with  a 
thick  mass  of  dead  seaweed,  which  rots  away 
and  smells  badly  when  the  tide  is  out.  There 
are  crowds  of  tiny  creatures — e.g.  allies  of 
sand-hoppers — working  away  among  this  de- 
caying seaweed;  but  the  ordinary  life  of  the 
shore-pools  has  been  smothered,  and  explora- 
tion in  this  kind  of  shore-haunt  is  rather  an 
acquired  taste.  There  are  shores  and  shores. 


THE  SCHOOL  OF  THE  SHORE  5 

Even  if  we  keep  to  the  shore  in  the  nar- 
rower sense  there  is  great  variety  of  condi- 
tions. Take  first  the  great  masses  of  rock 
which  often  run  far  out  to  sea.  Their  tops  and 
their  seaward  faces  are  exposed  for  the  greater 
part  of  the  day  to  the  full  violence  of  the  wind 
and  the  heat  of  the  sun ;  as  the  water  rises  the 
waves  beat  against  them,  and  they  are  only 
completely  submerged  for  a  short  time  at  very 
high  tide.  Yet  even  these  have  their  inhabit- 
ants. Behind  and  between  these  weather- 
beaten  masses  there  is  shade  and  moisture; 
sheltered  nooks  and  crannies  abound;  the 
smaller  rocks  at  their  bases  are  covered  with 
sea-wrack,  and  every  hollow  contains  a  quiet 
pool  of  water  left  by  the  receding  tide,  each 
pool  harbouring  a  crowded  life. 

Beside  the  rocks  are  the  great  stretches  of 
flat,  smooth  sand  where  we  have  built  castles 
and  dug  moats,  and  the  sands,  too,  have  their 
own  particular  population,  though  it  is  not 
always  easy  to  see  it.  Sometimes  instead  of 
sand  there  is  shingle,  gravel,  or  even  large 
pebbles  smoothed  or  rounded  by  the  action  of 
the  waves.  This  kind  of  shore  is  the  most 
unfavourable  of  all  to  animal  life.  We  shall 
easily  find  the  reason  for  ourselves  if  we  bathe 


6  THE  HAUNTS  OF  LIFE 

or  wade  among  the  surf  on  a  pebbly  shore, 
for  on  a  rough  day  we  may  come  out  of  the 
water  tingling  and  bruised  all  over  with  the 
continually  moving  stones. 

The  mud  flats  formed  at  river-mouths  by 
the  soil  carried  down  by  the  streams  have 
their  inhabitants  too,  as  we  can  easily  guess 
from  the  large  numbers  of  birds  that  are  busy 
feeding  there  at  low  tide. 

Finally,  there  is  the  most  populous  part  of 
the  whole  region,  the  stretch  of  flat  rocks  cov- 
ered with  the  great  seaweeds — from  which  the 
belt  takes  its  name — "the  laminarian  zone." 
A  part  of  this  region  is  not  uncovered  except 
at  very  low  tides. 


IN  DEEPER  WATERS  NEAR  SHORE 

In  warm  seas,  beside  a  coral-reef  for  in- 
stance, naturalists  have  been  able  to  work  for 
hours  at  a  depth  of  10  to  15  feet.  They  simply 
put  on  a  metal  hood  fitting  the  shoulders  and 
connected  with  a  compression-pump  on  the 
launch  above  by  means  of  a  long  hose-pipe 
which  allows  complete  freedom  of  movement. 
The  diver  breathes  freely  inside  his  hood,  and 
the  weight  of  it  is  greatly  reduced  in  the 


PLATE  I. — CROWDED  GROUP  OF  GUILLEMOTS,  ox  A  STACK  OF  ROCK,  FARNE  ISLANDS. 

Note  also  some  Kittiwakes. 
Photograph  by  NORRIE,  1'raserburgh. 


THE  SCHOOL  OF  THE  SHORE  7 

water.  It  is  possible  in  this  way  to  get  very 
near  the  animals,  and  to  watch  their  goings  on. 
Mr.  W.  H.  Longley  tells  of  his  experiences 
beside  a  tropical  coral-reef.  "  It  is  a  strange 
world  in  which  the  diver  finds  himself;  it  is  so 
small  and  still;  so  surrounded  with  mystery; 
so  surprisingly  unlike  that  which  one  imagines 
it  to  be,  observing  it  from  the  surface.  Even 
when  the  light  is  brightest,  and  the  water  most 
free  from  sediment,  one  never  sees  objects  at  a 
greater  distance  than  a  few  yards  (in  one  very 
favourable  case,  fifteen  paces) ;  and  if  a  heavy 
surf  is  pounding  a  short  distance  seaward,  so 
much  debris  may  be  borne  inshore  on  a  rising 
tide  that  one  may  be  shut  in  almost  as  com- 
pletely aa  in  a  blinding  snowstorm,  and  have 
no  means  of  finding  one's  way  back  to  the  boat 
other  than  following  the  hose.  No  sound 
reaches  one  save  that  of  the  air  rushing  into 
the  hood  at  each  stroke  of  the  pump  above. 
Graceful  Gorgonians  (i.e.  Sea-fans;  much 
branched,  flexible,  Alcyonarian  corals),  pur- 
ple, brown,  yellow,  or  olive,  may  sway  gently 
as  the  lazy  swell  rolls  overhead;  or,  as  one 
clambers  about  the  face  of  some  submerged 
escarpment,  one  may  see,  from  below,  sheets  of 
foam  spreading  where  trampling  rollers  raised 


8  THE  HAUNTS  OF  LIFE 

by  an  incessant  trade  wind  have  broken.  Yet 
all  transpires  in  perfect  silence."  One  feature 
that  contributes  to  the  strangeness  of  the  sur- 
roundings is  that  all  vertical  distances  prove 
to  be  much  greater  than  they  appear  from  the 
surface  of  the  water.  An  apparently  smooth 
floor  turns  out  to  be  rough,  and  a  rough  one 
is  found  to  be  seamed  by  ragged  crevasses. 

Mr.  Longley  tells  us  of  some  of  the  sights 
he  saw.  A  bit  of  food  thrown  on  to  the  sandy 
floor  would  tempt  crabs  out  of  hiding;  they 
would  scuttle  over  the  bottom  like  shadowy 
ghosts,  so  like  are  they  to  their  surroundings ; 
then  they  would  scrape  and  scratch  a  little 
with  their  hind  legs  and  go  down  backwards 
out  of  sight  Flounders,  coloured  and  pat- 
terned just  like  the  bottom,  would  rise  and 
sink  again,  burying  themselves  in  the  drifting 
sand,  all  but  their  protruding  watchful  eyes. 
From  a  tiny  hole  in  the  coral  a  small  fish 
"with  an  enormous  dorsal  fin  would  protrude 
half  its  body,  and  rapidly  and  repeatedly  ele- 
vate and  depress  its  great  banner,  while  an- 
other seems  to  respond  to  the  signal."  "  Often 
one  observes  incidents  which  remain  incom- 
prehensible, as  when  two  yellow  grunts 
(Hamulon  sciurus)  approach  one  another 


THE  SCHOOL  OF  THE  SHORF  9 

slowly,  snout  to  snout,  open  their  mouths  to  the 
limit  of  their  gape,  and  gaze,  as  it  seems,  for 
several  seconds,  as  if  in  rapt  attention,  each  at 
the  patch  of  bright  red  on  the  other's  mouth." 

A  near  view  shows  that  there  is  haunt 
within  haunt.  There  are  sandy  corners  and 
seaweedy  corners,  sheltered  coral  basins  and 
open  reefs,  shady  places  and  illumined  places, 
and  all  the  different  levels  from  the  floor  to 
the  surface.  Of  course  there  are  bold  wan- 
derers that  go  everywhere,  but  on  the  whole 
each  creature  has  its  favourite  and  habitual 
corner,  to  which  it  is  particularly  well  suited, 
especially  as  regards  its  colour  and  patterns. 
And  different  creatures  tenant  the  same  place 
at  different  times:  thus,  when  evening  ap- 
proaches, the  day-feeding  fishes  disappear, 
and  out  of  the  recesses  of  the  reef  come  night- 
feeding  fishes,  first  in  twos  and  threes,  and 
then  in  schools.  There  are  many  "  Box  and 
Cox"  arrangements  in  Nature. 

The  big  result  of  close  observation  of  the 
shore-haunt  is  to  show  that  it  includes  a  great 
variety  of  surroundings,  and  that  many  a  crea- 
ture has  a  particular  niche  where  it  is  most  at 
home. 


10  THE  HAUNTS  OF  LIFE 

A  REPRESENTATIVE  POPULATION 

Of  all  the  haunts  of  life,  the  shore  has  the 
most  representative  fauna  or  assemblage  of 
animals.  Almost  every  kind  of  creature  is 
there.  Let  us  begin  at  the  top  of  the  genea- 
logical tree. 

On  some  quiet  British  shores  the  seals  come 
out  of  the  water  to  rest,  and  are  sometimes 
caught  napping  by  men  who  have  no  mercy. 
They  bring  forth  their  young  ones,  usually 
one  for  each  mother,  in  caves  or  in  sheltered 
nooks  among  the  rocks;  and  this  tells  us  part 
of  the  secret  of  seals, — that  they  are  the  aquatic 
descendants  of  terrestrial  mammals.  For  it  is 
a  general  Natural  History  rule  that  animals 
go  back  to  their  old  home  to  breed.  What  is 
seen  on  a  small  scale  on  British  shores  is  seen 
magnified  elsewhere;  for  instance  in  Alaska, 
where  the  fur-seals  have  their  great  rookeries. 

On  other  British  shores  the  otter  has  its 
home,  or  rather  one  of  its  homes,  for  otters  are 
roving  animals.  They  often  swim  several 
miles  to  reach  an  island  off  the  coast;  they  can 
dive  more  than  full  fathoms  five  to  catch  the 
plaice  lying  on  the  sandy  floor  of  the  bay; 
when  they  are  severely  rationed  they  pick 


PLATE  II. — TERNS  OR  SEA-SWALLOWS,  FLYING  ON  THE  SHORE. 

Note  the  very  long  wings  and  the  forked  tail.     On  the  dunes  three  eggs 

may  be  seen  in  a  little  scraping  on  the  sand. 


THE  SCHOOL  OF  THE  SHORE          II 

about  among  the  rocks,  not  disdaining  limpets 
and  mussels. 

Besides  seals  and  otters  there  are  other 
mammals  that  frequent  or  may  frequent  the 
shore.  The  polar  bear  in  the  Arctic  regions 
sometimes  lies  down  beside  an  opening  in  the 
thick  ice  and  waits  for  a  seal  to  come  up  to 
breathe.  With  one  stroke  of  its  great  arm  it 
has  been  known  to  lift  the  seal  right  out  of 
the  water,  and  send  it  crashing  over  the  ice 
instantaneously  killed.  The  walruses,  also  of 
the  North,  dig  up  the  bivalves  with  their  huge 
tusks.  Along  warm  coasts  the  dugongs  and 
manatees,  jointly  known  as  sea-cows,  browse 
on  the  seaweeds.  But  we  have  said  enough: 
the  shore-fauna  includes  mammals. 

BIRDS. — There  are  many  birds  character- 
istic of  the  shore,  especially  at  certain  seasons. 
We  think  of  gulls  and  terns,  dunlins  and  sand- 
pipers, curlew  and  whimbrel,  shag  and  cor- 
morant, and  many  others — a  fine  account  of 
which  will  be  found  in  Mr.  W.  P.  Pycraft's 
delightful  book  The  Sea  Shore.  We  can  only 
select  a  representative.  The  oyster-catcher  is 
often  to  be  seen  where  there  are  limpets  and 
mussels  in  abundance.  The  black  and  white 


12  THE  HAUNTS  OF  LIFE 

plumage,  the  ruddy  legs,  the  red  and  yellow 
bill,  the  shrill  cry,  the  rapid  flight,  make  it 
very  conspicuous.  It  breaks  a  hole  in  one  valve 
of  the  mussel's  shell,  and  inserting  its  bill 
scoops  out  the  palatable  flesh.  With  a  dexter- 
ous side-stroke  of  its  strong  bill  it  can  jerk  the 
limpet  off  the  rock ;  but  to  do  this,  as  everyone 
knows  who  has  tried,  it  is  necessary  to  take 
the  mollusc  unawares  and  to  strike  quickly. 

REPTILES. — There  is  a  marine  lizard  (Am- 
blyrhynchus)  on  the  Galapagos  Islands  that 
swims  out  to  sea  and  dives  after  seaweed. 
There  are  sea-snakes  that  come  ashore  to 
bring  forth  their  young.  Crocodiles  and  alli- 
gators may  be  found  on  the  shores  of  estuaries. 
The  sea-turtles  bury  their  eggs  in  the  sand  of 
sun-baked  shores. 

AMPHIBIANS. — There  seems  to  be  some- 
thing about  salt  that  is  prejudicial  to  am- 
phibians. Thus  they  are  not  found  near  the 
sea  and  are  unrepresented  on  Oceanic  Islands, 
where  the  tenants  are  restricted  to  those  crea- 
tures that  could  survive  being  drifted  on  logs 
and  the  like,  or  could  be  carried  by  birds  or 
the  wind.  But  we  are  reminded  of  the  dan- 


THE  SCHOOL  OF  THE  SHORE          13 

ger  of  hard-and-fast  statements  by  the  fact 
that  there  is  a  frog  at  Manilla  which  is  often 
seen  hopping  about  on  the  shore. 

FISHES. — The  shore-fishes  are  legion,  but 
some  are  more  characteristic  than  others.  One 
of  these  is  the  Gunnel  or  Butterfish  (Gentro- 
notus  gunnellus),  so  extraordinarily  difficult 
to  catch  because  of  its  power  of  insinuating 
itself  between  the  stones  and  into  crevices,  so 
extraordinarily  difficult  to  hold  when  one  has 
caught  it,  such  is  its  slipperiness.  The  father- 
lasher  and  the  sand-eel,  the  cock-paidle  and 
the  stickleback  are  also  common  on  the  shore. 

SEA-SQUIRTS. — Fastened  to  the  long  flag-like 
seaweeds  there  are  often  groups  of  Ascidians 
or  Sea-Squirts,  strange  degenerate  creatures 
which  cross  the  frontier  into  the  backboned 
sub-kingdom  in  their  free-swimming  youth, 
but  sink  back  again,  as  it  were,  when  they 
grow  up  and  settle  down.  On  the  stones  at  low 
tide  there  are  often  very  beautiful  colonies 
of  compound  Ascidians  or  Tunicates,  quite 
jewel-like  sometimes  in  their  fine  colouring. 

MOLLUSCS. — Highest  in  a  way  among  back- 
boneless  or  Invertebrate  animals  are  the  Mol- 


14  THE  HAUNTS  OF  LIFE 

luscs — the  bivalves,  snails,  and  cuttlefishes; 
and  these — especially  the  first  two  classes — 
are  well  represented  on  the  shore.  Bivalves 
are  represented  by  cockle  and  mussel,  oyster 
and  clam ;  snails  by  the  vegetarian  periwinkle 
and  limpet,  and  the  car- 
nivorous dog-whelk  and 
buckie;  cuttlefish  by  an 
occasional  octopus  hunt- 
ing for  crabs  among  the 
low-tide  rocks.  Even 
Aristotle  knew,  over  two 
thousand  years  ago,  how 
a  shore  cuttle  shoots  out 
an  arm  and  grapples  a 
passing  fish. 

ARTHROPODS. — On 
quite  a  different  line  of 
life-  from   the   Molluscs 
FIG.   i.— THE  KING-CRAB, are    the    Jointed-Footed 
A^TZtShore    Animals  or  Arthropods, 
Arthropod.  represented  on  the  shore 

by  Crustaceans,  such  as  crab  and  hermit-crab, 
sea-slater  and  sand-hopper,  acorn-shells  and 
water-fleas.  Clambering  about  on  the  sea- 
weeds and  zoophytes  there  are  quaint  "  Sea- 


THE  SCHOOL  OF  THE  SHORE          15 

spiders"  or  Pycnogons,  perhaps  related  to 
both  true  spiders  and  Crustaceans.  A  few 
true  spiders  among  the  rocks,  some  insects 
near  high-tide  mark,  and  an  occasional  centi- 
pede must  also  be  included  in  the  shore-fauna. 

WORMS. — The  higher  worms  or  Ringed 
Worms  (Annelids)  are  well  represented  on 
the  shore;  but  one  must  dig  to  see  the  best 
of  them.  Thus  the  yard-long  many-footed 
Nereis  virens  burrows  in  the  sand  close  to  the 
rocks ;  the  castings  of  the  fisherman's  lobworm 
(Arenicola)  are  much  in  evidence  on  the  flat 
beach;  the  strange  sea-mouse  (Aphrodite), 
shaggy  with  iridescent  bristles,  is  often  cast 
up  from  greater  depths.  The  sand-binding 
worm  (Lanice  conchilega)  makes  tubes  of 
sand-particles  neatly  fastened  together;  the 
lime-tubes  of  Serpula  are  common  on  shells, 
and  of  Spirorbis  on  seaweed. 

Besides  the  higher  worms  or  Annelids,  with 
a  ringed  body,  there  are  many  others  of  lower 
degree.  Where  there  is  rotting  we  may  find 
thousands  of  small  threadworms  or  Nema- 
todes,  and  in  the  shore-pools  there  are  Plana- 
rians  or  "  living  films "  which  glide  along  mys- 
teriously by  means  of  invisible  lashes  or  cilia. 


1 6  THE  HAUNTS  OF  LIFE 

OF  UNCERTAIN  POSITION. — There  are  many 
seashore  animals  whose  relationships  are  ob- 
scure. Thus  there  are  the  Polyzoa,  to  which  the 
common  Sea-Mat  (F lustra)  belongs — the  ani- 
mal on  which  Darwin  wrote  his  first  scientific 
paper.  The  Polyzoa  form  a  large  class,  with 
a  great  variety  of  representatives,  some  sea- 
weed-like (F lustra),  till  you  look  into  them; 
some  coral-like  (Cellepora) ;  some  gelatinous 
(Alcyonidium)  ;  some  like  zoophytes  (Gemel- 
aria),  but  ever  so  much  higher  in  structure. 

ECHINODERMS. — The  prickly  skinned  ani- 
mals are  represented  by  star-fishes,  brittle-stars, 
sea-urchins,  and  sea-cucumbers,  forming  a  well- 
marked  "kenspeckle"  class,  with  a  great  tend- 
ency to  become  very  calcareous,  least  so  in  the 
sea-cucumbers,  most  in  such  sea-urchins  as  the 
sand-dollar.  It  is  a  most  interesting  sight  to 
watch  the  common  star-fish  creep  up  the  verti- 
cal surface  of  a  submerged  rock  by  means  of  its 
remarkable  hydraulic  locomotor  system,  while 
the  sea-urchin,  when  moving  on  a  flat  surface, 
hobbles  along  on  the  tips  of  its  five  teeth! 

STINGING  ANIMALS. — Sea-anemones  nestle 
like  flowers  in  the  niches  of  the  rocks.  In 


THE  SCHOOL  OF  THE  SHORE          17 

deeper  water  there  are  Alcyonarians,  such  as 
Dead-Men's-Fingers,  often  thrown  up  in  great 
quantities  after  searching  storms.  In  warmer 
seas  the  branched  Sea-fans  or  Gorgonians  are 
very  common.  Everywhere  there  are  zoophytes 
or  hydroid  colonies,  some  of  which  give  off 
swimming-bells  or  medusoids  in  the  summer 
season.  When  a  Stinging  Animal  (or  Coelen- 
terate)  becomes  very  calcareous  it  is  called  a 
coral,  and  so  there  are  corals  related  to  sea- 
anemones  (such  as  reef-building  corals  and 
cup  corals),  others  related  to  Alcyonarians 
(such  as  the  precious  red  coral  and  the  organ- 
pipe  coral),  others  related  to  hydroids  (such 
as  the  close-grained  millepores). 

SPONGES. — Apart  from  the  family  of  fresh- 
water sponges  (Spongillidae) — doubtless  emi- 
grants from  the  shore — all  sponges  are  either 
shore-animals  or  deep-sea  animals.  In  other 
words,  they  are  sedentary  and  require  a  sub- 
stratum on  which  to  grow.  The  Crumb-of- 
Bread  Sponge  (Halichondria  panlcea)  grows 
on  the  shore-rocks,  with  exhalant  openings 
like  the  craters  of  volcanoes ;  the  Purse  Sponge 
(Grantla  compressa)  often  has  to  endure  pro- 
longed exposure  at  low  tide;  the  Bath  Sponge 


1 8  THE  HAUNTS  OF  LIFE 

(Euspongia),  found  in  the  Mediterranean, 
the  West  Indies,  and  Australia,  often  grows 
at  depths  readily  reached  by  a  long  fork. 

SIMPLEST  ANIMALS. — Very  abundant  on 
some  shores  are  almost  microscopic  chalk- 
forming  animals  or  Foraminifers  which  glide 
about  on  seaweed  by  means  of  outflowing  and 
retractile  threads  of  living  matter.  In  all  the 
pools  and  shore-waters  there  are  many  kinds 
of  Infusorians,  which  propel  themselves  rap- 
idly by  means  of  lashes  of  living  matter  (cilia 
or  flagella). 

Any  book  on  shore  Natural  History  will 
supply  information  about  the  animals  on  our 
list.  The  meaning  of  the  list  is  just  to  show 
that  the  shore  gives  hospitality  to  a  very  rep- 
resentative assemblage  of  animals.  We  add  a 
scheme  of  classification,  which  may  be  useful 
at  different  parts  of  our  study,  to  show  how 
certain  animals  stand  in  relation  to  others. 


A  DIFFICULT  PLACE  TO  LIVE  IN 

The  school  of  the  shore  is  a  hard  school. 
It  must  be  an  interesting  and  stirring  place  to 
live  in,  but  no  one  could  call  it  easy.  There 


THE  SCHOOL  OF  THE  SHORE 


THE  ANIMAL  KINGDOM 


BIRDS. 
Flying  Birds.     Running  Birds. 

Placentals. 
MAMMALS.    *«*£ 
Monotremes. 

MANY-CELLED  ANIMALS,  WITH  BODY. 

Q* 
H 

fc 

Snakes.        Lizards.       REPTILES.  Crocodiles.  Tortoisesand 
New  Zealand  "  Lizard."        Turtles. 

BACKBO 

Mud-Fishes, 

FISHES,    ?«?y  -F!»h  e,?- 

Ganoids. 
Gristly  Fishes. 

Frogs. 
AMPHIBIANS. 
Newts.                 Caecilians. 

ROUND  MOUTHS. 
Hag.                     Lamprey. 

LANCELETS. 

SEA-SQUIRTS. 

BACKBONELESS. 

Spiders. 
Scorpions. 
Mites. 

Balanoglossus,  etc. 

Cuttlefishes. 
Gasteropods. 

MOLLUSCS. 
Bivalves. 

Insects. 
Millipedes. 
Centipedes. 
Peripatus. 

HIGHER  WORMS 
OR  ANNELIDS. 

SMALL  CLASSES. 

SMALL  CLASSES. 

SMALL  CLASSES. 

ARTHROPODS. 

Crustaceans. 

LOWER  WORMS. 

Feather-stars. 
Brittle-stars. 
Star-fishes. 

ECHINODERMS. 

Sea-Urchins. 
Sea-Cucumbers. 

Comb  Bearers         Jelly-fishes.        Sea-  Anemones  and  Corals, 
or  Ctenophores. 
STINGING  ANIMALS. 
Swimming  Bells  and  Zoophytes. 

SIMPLEST  ANIMALS. 
Infusoria            *-*-. 

SPONGES. 

ind               Malaria-animal, 
and  the  like. 

£* 

s° 

20  THE  HAUNTS  OF  LIFE 

are  stormy  days  when  the  waves  are  literally 
breakers.  There  are  fresh-water  floods  from 
inland,  smothering  masses  of  jetsam  from  the 
sea,  and  clouds  of  wind-driven  sand  from  the 
beach  and  the  dunes.  In  the  polar  regions 
there  are  difficulties  due  to  the  ice;  in  the 
equatorial  regions  there  are  difficulties  due  to 
the  scorching  sun. 

Many  problems  are  presented  by  the  differ- 
ences between  tide  in  and  tide  out:  animals 
that  have  been  bathed  in  water  for  many 
hours  are  left  high  and  dry.  Let  us  look  at 
a  few  of  the  solutions. 

All  animals  require  oxygen  to  keep  the  vital 
processes  agoing,  for  there  is  no  living  with- 
out combustion.  Oxygen  is  required  to  keep 
the  fire  of  life  burning.  Now  marine  animals 
find  the  indispensable  oxygen  mixed  with  the 
water,  and  seashore  water,  where  there  are 
waves,  is  very  rich  in  oxygen.  But  an  animal 
accustomed  to  use  the  oxygen  mixed  with  the 
water  cannot  suddenly  change  and  become 
able  to  use  the  oxygen  mixed  with  the  air. 
This  is  one  of  the  problems  raised  by  the  out- 
going tide. 

The   Purse   Sponge    (Grantla   compressa) 


THE  SCHOOL  OF  THE  SHORE    21 

keeps  a  big  bubble  of  water  in  the  cavity  of 
its  body,  and  this  serves  to  mediate  between 
the  living  cells  and  the  dry  air.  The  bivalves, 
like  mussels  and  oysters,  keep  the  two  halves 
of  the  shell  firmly  closed,  and  imprison  enough 
of  sea-water  to  keep  the  delicate  gills  and  skin 
moist  for  many  hours.  While  the  mussels  are 
uncovered  at  low  tide  the  shells  are  never 
opened,  and  the  animal  remains  quiet,  not 
feeding,  scarcely  breathing,  simply  waiting 
until  the  sea  returns.  Periwinkles,  buckies, 
and  many  other  sea-snails  have  a  very  effec- 
tive way  of  closing  their  shell  by  means  of  a 
hard  plate  attached  to  the  hind  end  of  the  mus- 
cular "foot."  When  the  animal  withdraws 
into  its  shell,  this  lid  (operculum)  closes  the 
mouth  of  the  shell  and  fits  very  neatly.  If  we 
watch  a  periwinkle  walking  about  on  the  floor 
of  a  pool  we  see  that  it  glides  along  on  its 
"foot,"  and  that  the  head  with  its  horns  is 
also  protruded.  But  if  we  pick  it  up  the  head 
and  the  foot  are  immediately  withdrawn,  and 
the  animal  is  safe  behind  its  closed  door. 

The  limpet  needs  no  door  to  its  shell,  be- 
cause it  clings  so  firmly  to  the  rocks  by  its 
sucker-like  foot  that  it  is  very  difficult  to  dis- 
lodge. Its  shell  is  so  thick  that  the  water  within 


22  THE  HAUNTS  OF  LIFE 

it  does  not  evaporate,  and  the  limpet  is  safe, 
too,  from  being  injured  by  the  waves.  But  it 
is  not  altogether  safe  from  other  animals,  for 
some  birds,  especially  the  oyster-catcher  or 
sea-pie,  have  discovered  exactly  the  kind  of 
sudden  sharp  stroke  of  the  bill  that  is  needed 
to  knock  a  limpet  off  its  rock,  and  once  it  has 
let  go  its  hold  it  is  a  helpless  victim.  When 
the  tide  covers  the  limpet's  rock  it  relaxes  its 
hold  and  slowly  moves  off  on  its  foot  to  the 
nearest  seaweed  patch  where  it  cuts,  with  the 
long,  toothed,  rasping  ribbon  or  file  in  its 
mouth,  the  grassy  blades  on  which  it  feeds. 
Before  the  tide  has  ebbed  it  makes  its  way 
back  to  its  rock,  if  it  has  not  wandered  too  far 
and  lost  its  way,  and  fixes  itself  in  the  exact 
spot  in  which  it  was  before.  In  some  cases  it 
keeps  to  this  spot  so  persistently  that  a  little 
pit  corresponding  in  size  and  shape  to  its  shell 
may  often  be  seen  in  the  rock.  Where  all  the 
rock  is  smooth  the  limpet  does  not  trouble  to 
return  to  its  starting-point,  for  every  spot  is 
very  much  the  same. 

Some  molluscs,  whose  shells  are  not  large 
enough  to  enclose  them  comfortably,  or  to 
protect  them  effectively,  have  learnt  to  bury 
themselves  in  the  sand,  and  so  to  secure  mois- 


THE  SCHOOL  OF  THE  SHORE          23 

ture  and  safety.  The  animal  which  lives  in 
the  familiar  razor-shell  of  our  shores  burrows 
straight  downwards  with  its  foot  into  the  sand, 
where  it  lies  so  well  concealed  that  it  is  not 
easy  to  discover  it  alive.  For  even  if  we  see 
above  the  sand  the  little  jet  of  water  it  shoots 
up  from  time  to  time  through  its  breathing 
tube,  the  animal  burrows  away  so  rapidly  that 
it  is  not  easy  to  reach  it. 

Still  more  remarkable  is  the  fact  that  some 
bivalves,  such  as  the  one  known  to  fishermen 
as  the  piddock,  burrow,  or  rather  bore,  into 
the  rocks  themselves.  We  can  see  their  holes 
very  easily,  especially  when  the  rock  is  one  of 
the  softer  kinds  such  as  sandstone,  and  we 
may  sometimes  see  the  breathing  tubes  of  the 
piddock  at  the  mouth  of  its  long  burrow;  but 
these  are  very  quickly  withdrawn  as^we  ap- 
proach. The  hole  is  too  narrow  and  long  for 
a  crab's  claw  or  a  bird's  bill,  and  the  animal 
can  only  be  got  at  by  breaking  open  the  rock. 

This  mollusc  uses  its  "foot"  for  burrowing 
into  the  rock  just  as  its  sand-burrowing  rela- 
tives do;  but  there  is  a  difference  in  the  foot. 
Though  it  looks  quite  soft,  it  has,  embedded 
in  its  muscular  substance,  a  layer  of  sharp, 
hard  crystals,  and  these  slowly  wear  away  the 


24  THE  HAUNTS  OF  LIFE 

rock  as  the  animal  patiently  scrapes.  The 
crystals  in  their  turn  are  worn  away  by  the 
rock ;  but  they  are  continually  being  renewed. 
Thus  by  means  of  this  adaptation  the  boring 
Pholas  secures  three  things:  first,  the  neces- 
sary moisture  and  shelter  from  sun  or  frost 
to  keep  it  alive  while  the  tide  is  out;  second, 
security  from  being  dashed  to  pieces  by  the 
waves;  and  third,  relative  safety  from  the 
attacks  of  hungry  enemies. 

Molluscs  are  not  the  only  animals  that  have 
learnt  these  ways  of  protecting  themselves. 
Many  worms  burrow  in  the  sand,  and  a  few 
bore  into  the  rocks.  Flexible  worms  cannot 
have  shells  in  the  strict  sense,  for  shells  are 
made  by  the  living  skin ;  but  they  often  build 
round  their  bodies  sheltering  tubes  of  lime  or 
of  grains  of  sand,  or  bits  of  shell  or  other  sub- 
stances cemented  together,  and  they  with- 
draw their  delicate  tentacles  into  these  when 
danger  threatens.  Fragments  of  the  different 
kinds  of  tubes  made  by  different  kinds  of 
worms  may  often  be  picked  up  on  the  shore. 

Crabs  and  some  of  their  relatives  have  also 
the  habit  of  burrowing  in  the  sand,  shovelling 
it  aside  with  their  great  claws  or  with  their 
legs.  The  big  crabs,  indeed,  do  not  need  this 


THE  SCHOOL  OF  THE  SHORE         25 

habit  much  for  protection,  for  their  thick, 
hard  shell  covers  the  gills  and  prevents 
evaporation;  they  are  sufficiently  active  to  be 
able  to  get  to  a  pool  or  a  sheltered  crevice 
under  a  rock  whenever  occasion  arises;  and 
their  strong  claws  and  pugnacious  spirit  are 
enough  to  keep  off  most  enemies  except  still 
bigger  crabs.  Some  of  the  other  members  of 
the  family,  however,  such  as  the  burrowing 
prawns,  tunnel  in  the  sand  near  low-tide 
mark,  and  live  an  almost  underground  life. 

THE  STRUGGLE  OF  THE  SHORE 

A  haunt  with  a  crowded  population  of  all 
sorts  and  sizes,  a  haunt  where  the  most  con- 
stant thing  is  change,  a  haunt  bristling  with 
difficulties  and  hemmed  in  by  limitations; 
there  is  bound  to  be  much  struggle  on  the 
shore.  But  we  should  try  to  make  it  clear  to 
ourselves  that  the  "  struggle  for  existence  "  is 
a  technical  phrase  which  includes  much  more 
than  a  life-and-death  competition  around  the 
platter,  much  more  than  what  we  get  a  sym- 
bol of  when  the  pigs  elbow  and  jostle  one 
another  at  the  feeding-trough ;  it  includes  all 
the  answers-back  that  living  creatures  make 


26  THE  HAUNTS  OF  LIFE 

to  the  difficulties  that  beset  them  and  the 
limitations  that  hem  them  in. 

The  struggle  on  the  shore  is  partly  for 
food — some  of  which  is  always  being  carried 
out  to  sea;  partly  for  foothold — for  a  good 
niche  is  a  treasure;  partly  for  the  oxygen 
mixed  with  the  water — the  oxygen  which  is 
always  necessary  to  keep  life  going;  partly 
against  risks  of  dislodgment,  smothering,  and 
drought;  partly  to  get  elbow-room  in  self- 
expression;  and  partly  to  secure  the  safety  and 
welfare  of  the  young  ones.  The  "  struggle  " 
is  sometimes  an  endeavour  after  well-being. 
It  may  be  with  fellows  of  the  same  kind — one 
hermit-crab  against  another;  it  may  be  with 
foes  of  quite  different  race — mussel  against 
star-fish,  limpet  against  oyster-catcher;  it  may 
be  between  animals  and  Fate — the  physical 
forces  of  wind  and  wave,  of  sand  and  sun. 
The  struggle  is  manifold. 

In  our  study  of  the  Wonder  of  Life  (1914) 
we  have  referred  to  the  struggle  for  foothold 
on  the  shore.  "  It  is  important,  for  instance, 
that  the  limpet,  which  makes  little  journeys 
in  search  of  seaweed  to  nibble,  should  not  go 
too  far,  else  it  will  not  find  its  way  back,  and 
will  have  lost  the  spot  which  its  shell  has 


THE  SCHOOL  OF  THE  SHORE          27 

grown  to  fit.  It  is  curious,  too,  to  see  the 
American  Slipper-Limpet  (Crepldula) — one 
growing  on  the  top  of  another  to  the  number 
of  four  or  five — suggestive  of  the  root-idea  of 
a  sky-scraper."  It  is  very  interesting  to  take 
a  stone  from  a  deep  pool,  or  from  the  floor  of 
the  sea  in  shallow  water  further  out,  to  see 
how  many  different  kinds  of  creatures  take 
advantage  of  this  pedestal.  One  stone  from 
Clare  Island  bore  fourteen  different  kinds  of 
"moss-animals"  or  Polyzoa. 

Truly,  the  shore  is  a  place  of  struggle.  Is 
there  any  other  haunt  where  we  see  so  clearly 
the  truth  of  Tennyson's  words — 

"  That  life  is  not  as  idle  ore, 
But  iron  dug  from  central  gloom, 
And  heated  hot  with  burning  fears, 

And  dipt  in  baths  of  hissing  tears, 
And  batter'd  with  the  shocks  of  doom 
To  shape  and  use." 

In  Memoriam. 

Some  one  said  long  ago  that  a  great  part  of 
life  is  connected  with  the  conjugation  of  the 
verb:  To  eat;  and  we  realise  how  true  this  is 
when  we  study  the  life  of  the  shore.  "  I  eat, 
thou  eatest,  he  eats  .  .  .  they  eat."  "  I  shall 
eat  ...  they  shall  eat"  "  I  have  eaten  .  .  . 
they  have  eaten."  "They  have  been  eaten." 


28  THE  HAUNTS  OF  LIFE 

It  is  fairly  safe  to  say  that  no  seashore  animal 
ever  says,  what  a  man  might  say  with  a  shark 
after  him :  "  I  shall  be  eaten."  It  is  certain  that 
none  ever  says:  "  I  have  been  eaten."  There  is 
grim  truth  in  this  saying  about  the  conjuga- 
tion of  the  verb:  To  eat;  but  the  truth  is  one- 
sided unless  we  remember  that  the  animals 
are  also  conjugating  the  verb:  To  love,  and 
often,  also,  the  verb  to  conquer.  "  Love  "  and 
"  Hunger,"  both  in  inverted  commas,  are  the 
pivots  on  which  all  life  swings. 

THE  CIRCULATION  OF  MATTER 

Animate  nature  is  run  on  what  may  be 
•called  a  scheme  of  successive  incarnations. 
Matter  is  always  passing  from  one  embodi- 
ment to  another,  and  nothing  is  ever  lost.  The 
minute  plants  free  in  the  water  and  the  fixed 
seaweeds,  great  and  small,  all  feed  on  the  sea 
itself  and  the  air  which  it  holds  in  solution. 
They  are  bathed  in  a  nutritive  solution  of  salts 
and  gases,  which  their  living  matter,  with  the 
help  of  the  sunlight,  lifts  on  to  the  plane  of 
life.  In  technical  language,  they  build  up 
carbon-compounds  by  photo-synthesis. 

But  animals  get  their  food  from  the  plants, 


THE  SCHOOL  OF  THE  SHORE    29 

or  from  remains  of  the  plants,  or  from  other 
animals  which  have  fed  on  plants.  So  one 
incarnation  or  embodiment  follows  another 
in  long  chains,  and  this  is  the  circulation  of 
matter. 

It  has  been  calculated  that — 

One  pound  of  cod  means  that  the  cod,  to 

make  it,  had  to  eat  ten  pounds  of 

whelk  or  buckie; 
One  pound  of  buckie  means   that  the 

buckie,  to  make  it,  had  to  eat  ten 

pounds  of  sea-worms; 
One  pound  of  worms  means   that  the 

worms,  to  make  it,  had  to  eat  ten 

pounds  of  vegetable  sea-dust. 
We  mean  by  the  vegetable  sea-dust  the 

microscopic  plants  and  their  remains. 

Sometimes  the  chain  is  longer,  sometimes 
shorter,  but  we  cannot  understand  the  econ- 
omy of  the  sea  at  all  until  we  get  a  firm  grip 
of  the  idea,  which  the  chemist  Liebig  first 
made  vivid,  of  the  circulation  of  matter.  It 
is  a  modern  version  of  what  one  of  the  Greek 
philosophers,  Heraclitus,  said:  ALL  THINGS 
FLOW. 


30  THE  HAUNTS  OF  LIFE 

CANNIBALISM  IN  THE  CRADLE 

The  struggle  for  existence  means  all  the 
answers-back  that  living  creatures  make  to 
surrounding  difficulties  and  limitations.  It 
includes  experiments  in  co-operation  and 
mutual  aid,  as  well  as  experiments  in  com- 
petition. At  one  time  it  may  take  the  form 
of  increased  parental  care;  at  another  time 
it  may  mean  a  sharpening  of  teeth  and 
claws. 

We  must  not  blink  those  cases  where  the 
struggle  is  terribly  keen — for  immediate  life 
or  death.  Let  us  take  an  instance.  Fastened 
to  the  rocks  there  are  great  bunches  of  chaffy 
capsules — the  egg-cases  of  the  Great  Whelk 
or  Roaring  Buckie  (Buccinum  undatum), 
whose  shell  children  hold  to  their  ears.  Some- 
times the  bunch,  made  by  several  whelks 
working  together,  is  as  big  as  one's  head.  In 
each  capsule  there  are  many  developing  eggs, 
and  as  these  hatch  out  into  larvae  they  turn 
upon  one  another.  Those  furthest  advanced 
eat  the  others — the  leaders  the  laggards — till 
only  a  few  are  left  in  each  capsule.  This  is 
struggle  to  the  death  at  the  very  threshold  of 
life.  It  is  cannibalism  in  the  cradle.  The 


THE  SCHOOL  OF  THE  SHORE          31 

empty  bunches  are  often  torn  off  by  the  waves 
and  thrown  up  on  the  beach.  If  a  capsule  is 
carefully  examined,  an  opening  will  be  seen 
on  the  inturned  flatter  side — the  opening  by 
which  the  surviving  larva?  emerged.  The 
same  grim  story  is  true  of  the  neat  vase- 
shaped  capsules,  first  pinkish  and  then  straw- 
coloured,  which  the  small  Dog  Whelk  (Pur- 
pura  lapillus)  fastens  to  the  rocks,  very  often 
to  the  under  side  of  a  shelf.  Many  are  called 
into  life,  but  few  are  chosen  to  survive. 

SHORE  SEAWEEDS 

It  is  a  great  sight  when  the  seaweeds  are 
uncovered  on  a  rich  foreshore  at  the  lowest 
tide  of  the  year.  If  we  put  on  old  clothes 
and  boots  and  wade  out  among  them,  very, 
very  cautiously,  because  of  the  slipperiness 
and  the  danger  of  concealed  deep  holes,  we 
get  our  reward,  especially  if  we  take  scientific 
imagination  as  our  staff.  We  find  ourselves 
in  the  midst  of  a  rich  and  varied  vegetation, 
part  of  which  is  older  than  the  hills.  We  are 
in  the  midst  of  the  plants  of  the  early  ages  of 
the  earth's  history. 

A  distinguished  Oxford  botanist,  Dr.  A.  H. 


32  THE  HAUNTS  OF  LIFE 

Church,  has  pictured  three  great  chapters  in 
the  history  of  plant-life. 

(I.)  After  the  earth  had  greatly  cooled 
down,  the  condensation  of  the  water  vapour 
formed  a  great  sea  covering  the  whole  surface 
of  the  earth.  In  this  sea  there  lived  minute 
single-celled  or  bodiless  green  plants,  each 
sufficient  unto  itself.  Some  of  these  Plankton 
plants  were  the  ancestors  of  those  which  now 
abound  near  the  surface  of  the  Open  Sea. 

(II.)  By  and  by  the  buckling  of  the  sea- 
covered  earth's  crust  brought  part  of  it  within 
reach  of  the  light,  and  supplied  an  illumined 
sea-floor  on  which  plants  could  fix  themselves 
and  grow  big.  This  was  the  beginning  of  the 
shore  vegetation,  the  beginning  of  a  sub- 
stratum, the  beginning  of  what  we  ordinarily 
call  sea-weeds.  And  as  they  were  fixed  crea- 
tures, it  was  necessary  for  them  to  show,  not 
only  means  of  self-preservation,  but  means  of 
dispersal,  ways  of  continuing  their  kind. 
Some  of  the  free-swimming  plants  that  settled 
down  grew  long  threads,  others  spread  out 
into  fronds,  others  forked  and  branched  like 
the  most  beautiful  lace.  Ages  passed,  and 
there  was  a  great  race  of  seaweeds.  Some  of 
those  now  living  are  a  hundred  feet  long. 


THE  SCHOOL  OF  THE  SHORE          33 

(III.)  According  to  Dr.  Church's  interpre- 
tation, the  gradual  raising  of  the  sea-floor  in 
certain  places  led  to  the  first  dry  land,  and 
some  of  the  seaweeds,  which  had  become  very 
complex  plants,  were  transformed  into  land 
plants.  If  this  is  true,  it  was  a  great  change. 
The  roots  of  seaweeds  are  only  anchors  or 
hold-fasts ;  they  would  require  to  be  equipped 
with  rootlets  and  root-hairs  for  absorbing  the 
water  and  salts  from  the  young  soil.  And  the 
whole  surface  of  the  sea-plant,  suited  for  ab- 
sorbing water  and  salts  all  over,  would  have 
to  become  the  gas-absorbing  surface  of  the 
land-plant.  Moreover,  there  would  need  to 
be  a  system  of  vessels  inside  the  pioneering 
land-plant  for  transporting  the  raw  materials 
and  the  manufactured  materials  from  one 
part  of  the  plant  to  another;  and  this  is  only 
beginning  in  seaweeds. 

Of  course,  when  we  speak  of  transforma- 
tion, we  must  not  think  of  the  old  stories  of 
the  yellow  frog  who  was  suddenly  turned  into 
a  fairy  prince,  or  of  the  followers  of  Diomede 
turned  into  birds,  which  a  scholar-naturalist 
has  identified  as  Shearwaters.  Nature's  is  no 
quick  magic,  but  here  a  little  change  and 
there  a  little  change,  so  gradually,  so  slowly, 


34  THE  HAUNTS  OF  LIFE 

that  if  living  man  had  seen  the  transformation 
he  would  have  said  that  the  living  creature 
was  not  changing  at  all. 

Whatever  the  history  of  seaweeds  may  have 
been,  they  are  splendid  and  beautiful  plants 
to-day — not  half  enough  appreciated.  But 
without  saying  more  about  this  we  may  notice 
an  important  fact  in  regard  to  their  colours. 
The  green  seaweeds  are  nearest  high-tide 
mark;  lower  down  the  brownish  ones  are  in 
the  majority;  most  of  the  red  ones  are  in  still 
deeper  water.  All  the  three  sets  have  got  the 
precious  green  pigment  or  chlorophyll,  which 
enables  the  plant  to  utilise  the  energy  of  the 
sunlight;  but  in  the  brown  and  red  seaweeds 
the  green  is  disguised  by  other  pigments. 
Some  say  that  these  other  pigments  help  the 
plant  to  make  the  most  of  the  decreasing  light, 
and  that  red  is  better  than  brown.  So  the  red 
seaweeds  are  most  abundant  in  the  deepest 
waters  where  the  light  is  least. 

FOOD-GETTING  ON  THE  SHORE 

What  food  supplies  are  available  for  ani- 
mals on  the  seashore? 

(i)  There  are,  first  of  all,  the  living  sea- 


THE  SCHOOL  OF  THE  SHORE          35 

weeds  on  which  some  animals  browse,  such  as 
the  Pellucid  Limpet  (Helcion  pellucidum), 
well  known  for  its  beautiful  blue-marked 
shell.  Some  animals  that  look  as  if  they  were 
eating  the  seaweed  are  feeding  on  microscopic 
plants  on  the  surface  of  the  fronds.  Along 
with  the  seaweeds  we  must  take  the  sea-grass, 
Zostera,  a  flowering  plant  very  abundant  in 
some  shore  waters.  (2)  There  is,  secondly,  the 
result  of  the  breaking  down  of  seaweeds  and 
sea-grass,  the  vegetable  debris,  the  plant-dust. 
(3)  There  is,  thirdly,  the  multitude  of  minute 
free-swimming  and  free-floating  plants,  such 
as  Diatoms  and  Desmids.  These  are  exceed- 
ingly abundant  in  near-shore  waters,  and  get 
swept  out  to  form  Open-Sea  Plankton.  The 
shore-waters  serve  as  a  nursery  for  the  Open 
Sea  abundance  of  minute  plants.  (4)  There  are 
the  minute  free-swimming  animals,  some  of 
which  are  hardly  distinguishable  from  plants. 
(5)  There  is  the  material,  both  animal  and 
vegetable,  brought  down  from  inland  by  rivers 
and  streams,  sometimes  helped  by  the  wind. 
We  are  not  including  the  mineral  matter 
brought  down  which  serves  to  feed  the  shore 
plants.  (6)  There  is  the  jetsam  brought  in  from 
the  sea,  for  the  receding  tide  sometimes  leaves 


36  THE  HAUNTS  OF  LIFE 

on  the  beach  countless  numbers  of  creatures 
that  have  come  too  near  the  shore.  We  have 
seen  a  brownish  line  of  millions  of  the  pinhead- 
like  Noctiluca  extending  far  along  the  sand. 

Sometimes  there  is  an  unexpected  windfall 
of  food!  Thus  one  writer  tells  us  that  a  hur- 
ricane lasting  for  days,  at  the  time  that  a  par- 
ticular moth  (called  the  nun)  was  swarming, 
blew  such  numbers  of  these  out  to  sea,  that, 
when  they  were  washed  up  by  the  tide,  their 
dead  bodies  formed  a  wall  6^  feet  broad  and 
6  feet  high,  which  stretched  for  many  miles 
along  the  shore.  The  same  kind  of  thing  has 
been  noticed  many  times  in  warmer  regions, 
when  the  locusts  were  caught  in  a  storm  dur- 
ing their  migration. 

But  there  is  one  thing  we  must  remember 
about  the  abundant  supply  of  food  on  the  sea- 
shore— it  is  not  very  regular,  and  it  never  lasts 
long  at  a  time.  The  incoming  tide  may  throw 
it  up  one  day  and  the  outgoing  tide  may  carry 
it  away  the  next — carry  it  so  far  that  it  is 
never  brought  back  again.  For  if  it  gets  be- 
yond the  shallow-water  area  it  sinks  to  the 
bottom  at  the  "mud-line."  It  is  not  wasted 
even  then — "Nature  is  ever  a  careful  house- 
keeper"; but  it  is  no  longer  available  for  the 


THE  SCHOOL  OF  THE  SHORE          37 

shore  animals.  So  these  have  to  be  on  the 
qui  vive;  they  must  feed  while  they  can,  and 
take  as  much  as  they  can.  No  doubt  they  can 
get  a  good  living,  but  they  cannot  get  it  easily. 
One  of  the  most  important  lessons  that  the 
inhabitants  of  the  shore  have  to  learn  is  to  be 
always  on  the  alert,  and  to  make  the  most  of 
their  chances. 

Let  us  take  some  particular  cases  of  food- 
getting.  Encrusting  the  rocks  in  many  places 
there  is  the  Crumb-of-Bread  Sponge  (Hali- 
chondria  panicea)  with  large  exhalant  aper- 
tures where  the  water  is  swept  out,  and  minute 
pin-prick  holes  all  over  the  surface  by  which 
the  water  is  swept  in.  After  their  early  youth  is 
past,  sponges  are  fixed  animals,  and  one  natu- 
rally thinks  of  them  as  easy-going.  But  they 
have  to  work  hard  for  their  living.  They  ob- 
tain their  food  from  microscopic  creatures  and 
nutritive  particles  in  the  water,  and  in  order  to 
get  enough  they  have  to  pass  large  quantities 
of  water  through  their  body  every  day.  If  an 
animal's  body  be  compared  to  a  city,  and  the 
tissues  to  streets,  and  the  cells  composing  the 
tissues  to  houses  and  workshops,  and  the  jos- 
tling particles  of  living  matter  inside  the  cells 
to  the  people  themselves,  we  would  compare  a 

78301 


3  8  THE  HAUNTS  OF  LIFE 

sponge  body  to  a  city  like  Venice,  which  is 
traversed  by  canals,  bringing  in  food  and  use- 
ful materials,  and  carrying  away  waste.  For  the 
sponge's  body  is  traversed  by  inhalant  canals, 
bringing  in  food  and  oxygen  (both  carried  by 
the  water),  and  bearing  out  useless  particles 
and  waste  products.  The  water,  as  we  have 
said,  passes  in  by  minute  pin-prick  holes  all 
over  the  surface  of  the  sponge;  it  passes  out  by 
the  large  openings  often  about  the  diameter  of 
a  lead-pencil.  If  a  glass  tube  be  carefully  fitted 
into  one  of  these  exhalant  apertures,  and  one 
need  not  be  afraid  of  hurting  the  sponge,  the 
water  will  be  forced  up  into  the  tube  above 
the  level  of  the  surface  of  the  pool.  Where 
does  the  force  come  from?  The  pressure  is 
due  to  the  ceaseless  activity  of  lash-bearing  or 
flagellate  cells,  situated  in  chambers  at  the 
junction  of  the  inhalant  and  exhalant  canals. 
On  their  lashing  the  whole  life  of  the  sponge 
depends.  Does  it  not  work  hard  for  its  living? 
The  sea-anemones  nestling  in  the  niches  of 
the  rocks,  some  of  them  like  chrysanthemums 
when  spread  out,  how  do  they  get  their  food? 
They  wait  for  creatures,  e.g.  small  crustaceans, 
to  touch  their  expanded  tentacles,  which  are 
covered  with  explosive  stinging-cells  and 


THE  SCHOOL  OF  THE  SHORE          39 

grappling-cells.  Just  as  we  draw  back  our 
finger  from  a  hot  plate  without  even  willing 
it,  because  of  a  circuit  between  nerve-cells 
that  feel,  nerve-cells  that  command,  and 
muscle-cells  that  obey,  so  the  sea-anemone 
folds  its  tentacles  about  an  incautious  worm. 
This  is  called  reflex  action.  The  sea-anemone 
may  be  deceived  by  giving  the  tentacles  a  little 
roll  of  wet  paper  to  catch;  but  after  it  has 
been  cheated  twice  or  thrice  it  has  had  enough 
and  will  not  close  up  any  more.  Sometimes  it 
catches  too  big  an  animal,  like  a  periwinkle, 
which  struggles  hard  and  bursts  through  the 
enswathing  tentacles.  The  sea-anemone  can 
flourish  for  a  long  time  without  more  than 
microscopic  food;  it  might  be  called  an  easy- 
going feeder.  One  has  been  known  to  live  for 
sixty  years. 

Right  up  to  the  high-tide  mark  on  rocks, 
pillars  of  piers,  stray  pieces  of  wood,  and  even 
on  living  animals,  like  crabs,  we  see  a  crusting 
of  rock-barnacles  or  acorn-shells.  When  the 
tide  is  out  the  roof  of  the  rampart  that  encloses 
the  animal  is  kept  tightly  shut;  but  as  soon  as 
the  water,  or  even  the  salt  spray,  reaches  it, 
the  acorn-shell  opens  its  four  valves.  When  it 
is  covered  with  water  it  begins  to  feed  without 


40  THE  HAUNTS  OF  LIFE 

losing  a  minute,  and  we  are  rewarded  if  we 

kneel  down  beside  a  pool  and  watch  operations. 

From  between  the  valves  there  are  protruded 


FIG.  2. — ACORN-SHELLS  OR  ROCK-BARNACLES  (BALANUS). 
Of  two  kinds,  large  and  small.     Notice  the  Outer  Rampart, 
the  Movable   Roof  of  four   pieces,   and   the   six   pairs   of 
Curled  Feet  wafting  the  Food  into  the  Mouth. 

six  pairs  of  curl-like,  bristle-bearing  limbs, 
each  with  two  branches;  and  with  this  sift- 
ing net  the  little  crustacean  sweeps  the  water, 


THE  SCHOOL  OF  THE  SHORE          41 

wafting  minute  creatures  and  nutritive  parti- 
cles into  its  mouth.  Professor  Huxley  com- 
pared the  acorn-shell  to  a  shrimp  fixed  head- 
downwards,  and  kicking  its  food  into  its 
mouth  with  its  legs.  But  it  is  a  peculiarly 
graceful  kind  of  kicking!  Many  of  them  must 
expend  much  energy  before  they  sift  out  a 
meal  from  the  clear  water.  They  live  in  cas- 
tles; but  not  castles  of  indolence.  The  acorn- 
shells  are  relatives  and  probably  descendants 
of  the  stalked  barnacles  which  fix  themselves 
to  wooden  ships  and  floating  logs.  Like  these 
they  are  free-swimming  in  their  early  youth; 
but  they  fix  themselves  eventually  by  their 
feelers  and  settle  down.  A  rampart  of  lime 
is  formed  round  about,  and  the  animal  is 
cemented  down  for  the  rest  of  its  life.  Not  a 
very  exciting  life,  perhaps,  but  a  very  safe 
one,  for  no  waves  are  strong  enough  to  wash 
the  barnacle  from  its  rock.  Sea-urchins  have 
meals  of  barnacle  when  they  are  tired  of  sea- 
weeds, and  dog-whelks  also  browse  on  them; 
but  they  hold  their  own  well.  Their  eggs  are 
washed  out  by  the  tide  and  hatch  in  the  open 
water,  and  there  we  also  find  the  transparent 
feather-like  moults  of  the  adults  which  have 
been  cast  in  the  pools. 


42  THE  HAUNTS  OF  LIFE 

Sponges,  sea-anemones,  acorn-shells  are  fixed 
animals,  and  they  depend  for  food  on  what 
they  can  sweep  in  from  the  water,  or  on  what 
they  can  catch  as  it  passes  by.  But  we  must 
take  some  examples  of  more  vigorous  ways  of 
feeding  on  the  part  of  animals  which  roam 
about  from  place  to  place.  The  periwinkles, 
such  as  Littorina  littorea,  which  is  one  of  the 
poor  man's  "oysters,"  creep  about  browsing 
on  delicate  seaweeds,  and  it  may  be  noticed 
that  those  sea-snails  which  have  an  unbroken 
outline  to  the  mouth  of  their  shell  are  vege- 
tarian, while  those  with  a  deeply  in-cut  notch 
at  the  mouth  of  the  shell  (a  groove  for  the  pro- 
trusion of  a  breathing  tube)  are  carnivorous. 
The  vegetarian  Gasteropods  are  palatable;  the 
carnivorous  ones  hardly  ever.  So  if  we  are 
wrecked  on  a  desert  island  we  must  begin  our 
seashore  meals  with  those  sea-snails  that  have 
no  notch  at  the  mouth  of  their  shell. 

Very  different  from  the  periwinkles  are  the 
whelks  and  "buckies"  which  roam  about  in 
search  of  animal  food.  We  often  find  on  the 
sandy  beach  one  of  the  valves  of  a  bivalve 
shell,  e.g.  Venus  Gallina,  with  a  hole  neatly 
bored  through  it,  as  neatly  as  if  it  had  been 
made  by  a  gimlet.  In  many  cases  this  hole 


THE  SCHOOL  OF  THE  SHORE          43 

has  been  made  by  a  carnivorous  Gasteropod 
called  Natica,  which  has  a  boring  gland  on 
the  underside  of  its  proboscis.  This  gland  is 
pressed  against  the  bivalve  shell  and  the 
sulphuric  acid  which  it  secretes  dissolves  a 
hole  right  through.  When  the  perforation  is 
made,  the  borer  often  uses  its  rasping  ribbon 
to  enlarge  it. 

THE  STORY  OF  THE  ANGLER 

One  of  the  queerest  of  queer  fishes  is  the 
Angler  or  Fishing  Frog  (Lophius  piscatorius) 
— a  fish  that  fishes.  It  is  rather  a  lazy  crea- 
ture, of  long  pedigree,  and  of  big  appetite.  In 
shallow  water  off-shore  it  often  shuffles  along 
with  its  strong  fore-fins  and  settles  down  on 
an  open  space  among  the  seaweed.  Curious 
tags  of  skin  about  the  head  and  body  are  very 
like  waving  fronds  of  seaweed,  and  that  is  all 
to  the  good.  The  first  three  fin-rays  of  the 
dorsal  fin  are  long  separate  rods,  and  the  first, 
which  is  particularly  mobile,  bears  a  lappet 
of  skin  dangling  at  the  free  end — the  bait  at 
the  end  of  the  angler's  line.  Circumstantial 
evidence  points  to  the  conclusion  that  the 
angler  really  fishes  with  its  fishing-rod.  In 


44  THE  HAUNTS  OF  LIFE 

some  of  its  deep-sea  relatives  the  bait  or  lure 
is  luminescent.  Fishes  are  often  attracted  to 
dangling  objects,  which  doubtless  pull  the 
trigger  "Food."  But  whatever  be  the  pre- 
cise use  of  the  fishing-rod  there  is  no  doubt 
that  the  angler  catches  many  fishes. 

The  creature's  head  is  extraordinarily  broad, 
and  its  gape  is  a  terror.  The  angler  seems 
"All  Mouth."  A  fatal  gape  it  is,  for  the 
sharp  teeth  along  the  jaws  point  backwards 
and  are  hinged  at  their  base,  yielding  at  once 
if  we  press  them  inwards,  but  rising  in  opposi- 
tion if  we  draw  our  finger  the  other  way.  What 
a  simple  trap,  and  yet  so  subtle!  A  broaden- 
ing out  of  the  jaws  is  not  very  remarkable ;  but 
add  to  that  a  fishing-rod  and  a  loose-hinged 
attachment  of  the  backward-pointing  sharp 
teeth.  If  the  incautious  victim  has  begun  to 
explore  what  must  seem  to  it  just  an  interest- 
ing opening  below  the  dangling  lure,  there  is 
no  return.  In  some  cases  the  Fishing  Frog 
manages  to  submerge  much  of  its  clumsy  body 
in  the  sand.  The  dorsal  fin-rays  stand  out  in 
all  innocence;  the  bait  dangles  above  the 
mouth ;  the  victim  indulges  its  scientific  spirit 
of  investigation — and  then  the  trap  snaps. 

The  eggs  of  the  angler  are  found  floating  in 


THE  SCHOOL  OF  THE  SHORE          45 

the  open  sea,  embedded  in  little  compartments 
in  a  big  drifting  sheet  of  violet-grey  slime, 
many  feet  long.  After  a  while  the  eggs  be- 
come separated  from  the  sheet  and  float  singly. 
The  newly  hatched  young  one  floats  also,  with 
its  heavy  head  downwards  (see  Fig.  7,  p.  93), 
'and  the  tip  of  its  tail  just  touching  the  surface 
film.  It  is  still  living  on  the  yolk  of  the  egg 
which  is  uppermost  in  the  water.  After  a 
fortnight  has  passed  the  yolk  is  exhausted;  the 
young  fish  is  superficially  like  a  tadpole;  it 
opens  its  mouth  and  begins  to  fend  for  itself. 
For  a  long  time,  however,  it  lives  an  Open- 
Sea  life,  and  it  has  an  extraordinary  appear- 
ance, due  to  the  elongation  of  its  fin-rays  into 
flexible  streamers.  These  have  the  same  use 
as  the  slime  round  the  eggs,  they  secure  flota- 
tion, first  at  the  surface,  and  then  in  the  upper 
layers.  This  is,  on  the  whole,  a  very  safe 
cradle,  and  there  is  an  abundance  of  living 
minutiae  to  eat.  Gradually  the  head  of  the 
larval  angler  broadens  out  enormously  behind 
the  eyes,  and  these  are  shifted  to  the  top.  The 
seaweed-like  tags  of  skin  become  numerous, 
the  long  fin-tassels  disappear.  The  young  fish 
comes  near  shore  and  sinks  to  the  bottom — 
there  to  remain  for  the  rest  of  its  life. 


46  THE  HAUNTS  OF  LIFE 

THE  STAR-FISH  AND  SEA-URCHIN  FIGHT 

The  star-fish  is  a  soft-mouthed  animal,  with- 
out anything  in  the  way  of  teeth  or  jaws,  but 
it  is  a  thoroughgoing  carnivore.  It  does  much 
harm  on  the  oyster-beds,  engulfing  the  small 
oysters  in  its  capacious  protrusible  stomach. 
It  is  fond  of  mussels,  and  it  can  actually  open 
the  valves  by  hunching  itself  up  above  the 
mussel  and  persistently  pulling  in  opposite 
directions  with  the  suctorial  tube-feet  of  two 
of  its  arms.  But  who  would  think  of  a  star-fish 
tackling  a  small  sea-urchin,  covered  all  over 
with  spines  like  a  hedgehog,  and  equipped 
with  hundreds  of  little  snapping  blades  (called 
pedicellariae),  like  scissors  with  three  blades. 
When  these  snapping  spines  are  touched,  they 
clinch;  and  some  of  them  are  poisonous. 

Nothing  daunted,  if  we  dare  use  such  a 
phrase  in  regard  to  an  animal  that  has  not  a 
vestige  of  brains,  not  even  one  nerve-centre, 
the  star-fish  lays  one  of  its  arms  on  the  prickly 
sea-urchin.  The  hundreds  of  tube-feet  on  the 
under  surface  of  the  arm  are  promptly  nipped 
by  the  sea-urchin's  snapping  spines.  The  star- 
fish withdraws  its  arm,  and  the  snapping 
spines,  unable  to  let  go,  are  wrenched  off. 


THE  SCHOOL  OF  THE  SHORE          47 

Then  another  arm  is  used,  and  another,  and 
another,  until  the  star-fish  has  disarmed  the 
small  sea-urchin.  Then  out  comes  the  elastic 
digestive  stomach.  This  shows  remarkable 
persistence  on  the  part  of  a  brainless  animal. 

SHIFTS  FOR  A  LIVING  ON  THE  SHORE 

Of  all  the  haunts  of  life  the  shore  is  most 
varied  in  its  life-saving  devices.  We  like  to 
call  them  "shifts  for  a  living,"  because  they 
are  on  so  many  different  levels  of  behaviour. 
In  some  cases  the  animal  probably  knows 
what  it  is  doing,  in  some  dim  way  at  least,  as 
when  a  crab  deliberately  rubs  pieces  of  sea- 
weed on  the  back  of  its  shell  so  that  they  catch 
on  the  bristles  and  grow  there.  In  other  cases 
the  animal  probably  does  not  know  what  it  is 
doing,  as  when  the  star-fish  surrenders  an  arm 
that  is  seized. 

What  an  armoury  of  weapons  there  is  on  the 
shore — stinging-cells  of  sea-anemones,  the 
lasso  of  a  ribbon-worm,  the  forceps  of  a  crab, 
the  rasping  file  of  a  whelk,  the  parrot's-beak- 
like  jaws  of  a  cuttlefish,  and  so  on  up  to  the 
tusks  of  a  walrus.  What  a  variety  of  armour 
too, — the  prickly  test  of  a  sea-urchin,  the  or- 


48  THE  HAUNTS  OF  LIFE 

nate  carapace  of  a  rock-lobster,  the  unbreak- 
able shells  of  molluscs,  the  scales  of  fishes 
often  sharp  and  formidable,  and  so  on  up  to 
the  complicated  encasement  of  the  edible 
turtle. 

MASKING 

The  "walking  wood  of  Birnam"  was  an 
episode  in  Scottish  history,  immortalised  in 
Shakespeare's  Macbeth,  where  a  band  of  sol- 
diers camouflaged  themselves  by  cutting  down 
branches  of  trees  and  carrying  these  with  them 
as  they  stealthily  advanced.  So  some  crabs  on 
the  seashore  fix  seaweeds  on  the  back  of  the 
shell  and  mask  themselves  effectively.  They 
can  steal  upon  their  victims;  they  can  efface 
themselves  in  the  eyes  of  their  enemies.  Some- 
times the  cloak  consists  of  zoophytes,  or  pieces 
of  sponge,  or  half  of  the  tunic  of  a  sea-squirt; 
but  oftenest  it  is  a  cloak  of  seaweed.  It  is  as 
if  the  crab  carried  a  garden  on  its  back.  The 
camouflaging  is  often  shown  by  the  sand-crab 
(Hyas  araneus)  and  by  the  narrow-beaked  crab 
(Stenorhynchus  longlrostrls]  ;  but  it  is  seen  in 
many  others.  The  disguising  seems  very  de- 
liberate on  the  crab's  part,  and  if  the  disguise 
is  picked  off,  the  crab  often  sets  about  clothing 


THE  SCHOOL  OF  THE  SHORE          49 

itself  again.  One  of  the  hermit  crabs  (Pagurus 
cuanensis)  in  deeper  water  has  its  borrowed 
shell  frequently  surrounded  by  a  bright  orange 
sponge  (Suberites  domuncula],  with  a  strong 
odour,  a  disagreeable  taste,  and  countless 
flinty  needles — which  fishes  naturally  leave 
alone! 

A  LIMB  FOR  A  LIFE 

Many  different  kinds  of  animals,  especially 
those  with  rather  lanky  limbs,  practise  a  curi- 
ous kind  of  surrender — a  limb  for  a  life.  And 
what  they  surrender  as  a  ransom  for  their  life 
they  can  regrow  at  leisure. 

This  is  well  illustrated  by  many  star-fishes. 
If  an  arm  is  pinned  down  by  a  stone,  or  seized 
by  an  enemy,  or  if  a  sea-slug  has  settled  on  an 
arm  and  cannot  be  dislodged,  the  star-fish 
manages  to  break  off  the  arm  at  the  base.  In 
so  doing  it  is  behaving  as  we  behave  when  we 
draw  back  our  finger  from  a  very  hot  plate,  or 
shut  our  eye  when  a  stone  is  about  to  strike  it, 
or  cough  when  a  crumb  of  bread  threatens  to 
"  go  down  the  wrong  way."  We  do  not  think 
about  doing  any  of  these  things  nor  exercise 
our  will ;  what  we  do  is  called  a  reflex  action, 
carried  out  by  means  of  pre-arranged  linkages 


5o  THE  HAUNTS  OF  LIFE 

of  nerve-cells  and  muscle-cells.  So  is  it  in  the 
star-fish  when  it  surrenders  an  arm.  We 
know  that  the  star-fish  does  not  do  this  delib- 
erately, for  it  has  a  very  poorly  developed 
nervous  system.  There  is  a  strand  of  nerve- 
cells  up  the  middle  line  of  the  under  surface 
of  each  arm,  and  these  are  united  in  a  pen- 
tagon around  the  mouth;  there  are  also  many 
scattered  nerve-cells;  but  there  is  no  brain, 
not  even  a  single  nerve-centre  or  ganglion. 
The  star-fish  does  not  know  what  it  does,  but 
it  has  somehow  in  its  constitution  learned  in 
the  course  of  time  that  it  is  better  that  one 
member  should  perish  than  that  the  whole  life 
should  be  lost.  Brittle-stars  give  off  their 
arms  very  readily;  sea-cucumbers  are  less  po- 
lite, for  they  discharge  their  insides  in  the 
spasms  of  capture;  sea-urchins  have  nothing 
that  they  can  give  away  save  their  spines.  We 
see  the  same  sort  of  surrender  when  the  lizard 
gives  off  its  tail,  and  we  find  many  cases 
among  insects  and  spiders.  It  is  very  marked 
in  the  harvest-men,  who  stalk  about  in  the 
evening  among  the  stubble,  with  legs  over 
twenty  times  the  length  of  their  body.  The 
self-mutilation  ("autotomy")  is  also  very 
common  among  Crustaceans. 


THE  SCHOOL  OF  THE  SHORE          51 

A  common  accident  on  the  seashore  is  that 
a  crab  gets  its  leg  badly  broken  by  a  moving 
stone.  When  that  happens  the  crab  goes  in 
for  surgery.  By  a  very  forcible  contraction 
of  the  muscles  at  the  base  of  the  damaged  leg 
the  crab  manages  to  break  it  off  across  a  weak 
line.  And  just  below  this  breaking  line  there 
is  inside  the  base  of  the  leg  a  two-flapped 
membrane  which  closes  up  the  wound  and 
prevents  bleeding.  Inside  the  bandage  a  new 
leg  is  formed  in  miniature,  and  at  the  next 
moult  this  shoots  out  like  a  Jack-in-the-box, 
and  soon  hardens. 

COLOUR  CAMOUFLAGE 

The  common  shore-crab  (Carcinus  meznas) 
occurs  in  many  colours  when  it  is  young,  and 
these  sometimes  harmonise  exactly  with  the 
rock  of  the  pool  in  which  the  particular  crab 
lives.  But  there  is  no  change  of  colour  except 
after  a  moult.  It  is  different  with  the  Aesop  / 
Prawn  (Hippolyte  varians)  which  takes  on 
the  colour  of  its  surroundings,  both  when 
young  and  when  adult,  and  can  change  from 
one  colour  to  another  with  ease.  It  has  a  large 
repertory — red,  yellow,  blue,  orange,  olive, 


52  THE  HAUNTS  OF  LIFE 

violet,  brown,  and  green,  and  it  is  often 
almost  perfectly  self-camouflaged  among 
brightly  coloured  seaweeds. 

Not  less  subtle  is  the  rapid  change  of 
colouring  and  pattern  in  flat  fishes  like  plaice 
and  dab.  Very  quickly  they  put  on  the  hue 
and  the  marking  of  the  sand  or  shingle  on 
which  they  are  resting.  When  on  sand  they 
usually  cover  themselves  quickly,  all  except 
the  eyes  which  protrude  and  look  about. 
Blind  flat  fishes  do  not  change  colour,  so  we 
know  that  the  message  from  the  outside  world 
first  affects  the  eye.  It  travels  to  the  brain, 
and  by  the  nervous  system  to  the  colour-cells 
in  the  skin  which  can  change  their  size  and 
position.  In  some  instances  the  change  oc- 
curs in  a  minute  or  two,  and  it  gives  the  fish 
a  garment  of  invisibility. 

In  the  aquarium  at  New  York  there  is 
often  a  startling  display  of  coral-reef  fishes 
from  the  Bermudas  and  similar  places.  Their 
colours  are  brilliant,  and  their  patterns  are 
almost  incredible.  It  seems  to  some  natu- 
ralists quite  impossible  that  these  colours  and 
patterns  can  have  concealing  value,  partly 
because  they  are  so  conspicuous,  one  might 
almost  say  daring,  and  partly  because  they 


THE  SCHOOL  OF  THE  SHORE          53 

differ  so  much  in  fishes  from  the  same 
reef. 

So  it  has  been  suggested  that  they  are 
warning  colours,  useful  in  impressing  enemies 
with  the  fact  that  many  of  these  brilliant 
fishes  are  unpalatable  and  best  left  alone. 
And  another  view  is  that  coral-reef  fishes  are 
so  safe,  with  so  many  holes  and  corners  to 
play  hide-and-seek  in  that  they  can  afford 
to  be  any  colour.  On  this  view,  the  colours 
are  of  no  more  use  than  the  colours  of  wither- 
ing leaves. 

On  the  other  hand,  Mr.  W.  H.  Longley, 
who  has  walked  about  on  the  floor  of  the  coral 
sea  and  watched  the  fishes  for  hours,  main- 
tains that  many  of  the  most  brilliantly  col- 
oured are  very  well  camouflaged  when  they 
are  in  the  particular  kind  of  corner  that  they 
like  best  as  a  home.  Some  have  two  kinds  of 
coloured  pattern,  suited  for  two  haunts — a 
sort  of  Jekyll  and  Hyde  business.  Some  are 
longitudinally  striped  or  with  no  pattern 
when  on  the  move  and  cross-striped  when  they 
settle  down.  It  looks  as  if  there  was  a  great 
deal  of  useful  camouflaging. 


54  THE  HAUNTS  OF  LIFE 

LOVE  ON  THE  SHORE 

The  business  of  living  creatures  is  two-fold 
— caring  for  self  and  caring  for  others.  Per- 
haps we  have  said  enough  about  caring  for  self 
on  the  shore;  what  about  caring  for  others? 
The  mother-seals  nurse  their  young  ones 
among  the  rocks,  and  many  birds,  such  as  guil- 
lemots and  razor-bills,  puffins  and  kittiwakes, 
make  their  nests  on  the  cliffs.  When  we  see  the 
narrow  ledges  on  which  the  guillemots  and  the 
razor-bills  lay  their  eggs — just  one  for  each 
bird — we  wonder  that  there  is  any  successful 
hatching  at  all.  The  wind  searches  every 
shelf,  and  there  is  such  a  crowded  coming  and 
going  of  mothers  that  the  egg  has  every  chance 
of  being  jostled.  But  Darwin  asked  natu- 
ralists to  notice  the  pear-like  shape  of  the  egg 
and  the  particular  way  in  which  it  moves 
when  it  is  twirled  in  an  eddy  or  jostled  by  the 
bird's  feet.  Because  of  its  shape  it  tends  not  to 
roll,  but  simply  to  rotate  on  its  short  axis  with- 
out moving  from  its  place.  If  we  give  it  a 
vigorous  twirl  on  a  smooth  table,  it  simply 
rotates  without  rolling.  For  this  reason,  then, 
it  does  not  fall  off  the  narrow  ledge  into  the 
sea.  This  is  a  simple  example  of  what  is 


THE  SCHOOL  OF  THE  SHORE          55 

meant  by  a  fitness  or  adaptation — some  pecu- 
liarity of  structure  or  habit  which  is  particu- 
larly well  suited  for  special  conditions  of  life; 
and  one  of  the  pleasures  of  Natural  History 
lies  in  the  discovery  of  these  fitnesses. 

The  turtles  come  ashore  from  the  warm  seas 
and  lay  their  eggs  in  the  sand,  and  the  mothers 
linger  till  their  young  ones  are  hatched.  The 
Edible  Turtle  is  a  vegetarian,  living  on  sea- 
weeds, and  must  therefore  keep  within  the 
shore-area  in  the  wide  sense.  It  has  not  far 
to  migrate  when  the  time  of  egg-laying  draws 
near.  But  the  fish-eating  turtles  of  the  Open 
Sea,  like  the  Hawksbill  Turtle  and  the  Snap- 
ping Turtle,  often  make  long  journeys  before 
they  find  suitable  places  for  egg-laying  on  the 
shores  of  island  or  continent 

The  venomous  sea-snakes,  well  known  in  the 
Indian  Ocean,  are  tenants  of  the  Open  Sea, 
but  some  of  them  at  least  come  to  the  shores 
at  the  breeding  season.  They  do  not  lay  eggs 
as  the  turtles  do,  but  bring  forth  their  young 
as  fully  formed  little  snakes,  and  it  is  interest- 
ing to  know  that  the  mother  often  remains  for 
a  while  with  her  children,  until  they  are  able 
to  fend  for  themselves  and  follow  her  out  to 
sea.  This  is  what  we  mean  by  "  love"  on  the 


56  THE  HAUNTS  OF  LIFE 

seashore,  and  however  big  we  make  the  in- 
verted commas  we  cannot  persuade  ourselves 
that  the  maternal  care  of  the  sea-snakes  is  not 
on  the  same  line  as  that  of  any  human  mother, 
vastly  finer  as  that  usually  is. 

The  quaint  fish  called  the  Lumpsucker  or 
Cock-Paidle  (Cyclopterus  lumpus)  lays  a  big 
bunch  of  reddish  eggs  in  a  corner  of  a  deep 
rock-pool  low  down  on  the  shore,  and  over 
this  the  father  mounts  guard,  driving  away 
intruders.  Every  now  and  then  he  lashes  with 
his  tail  very  vigorously  beside  the  mass  of 
eggs,  and  this  no  doubt  helps  to  aerate  the 
eggs  and  to  scatter  away  the  minute  particles 
of  mud  which  might  settle  upon  them.  The 
Lumpsucker  has  had  its  hind  fins  (pelvic  fins) 
shunted  forwards  and  turned  into  a  strong 
muscular  sucker,  and  he  can  grip  a  rock  when 
he  is  paddling  vigorously  with  his  tail.  We 
suppose  the  Scots  name  Cock-Paidle  refers  to 
this  paddling  of  the  cock-fish.  His  paternal 
duties  occupy  him  for  several  weeks,  and  ob- 
servers say  that  while  he  is  on  guard  he  neg- 
lects his  own  meals. 

There  are  sticklebacks  on  the  shore  as  well 
as  in  fresh  water,  and  the  males  make  nests  and 
mount  guard  over  them,  but  this  story  will 


THE  SCHOOL  OF  THE  SHORE    57 

keep  till  we  come  to  the  fresh-water  haunt. 
Less  familiar  is  the  case  of  a  tropical  shore-fish 
(the  Gaff  Topsail) ,  which  has  only  a  few  eggs, 
and  lives  in  places  where  the  struggle  for 
existence  is  very  keen.  What  is  it  to  do?  The 
male  fish  takes  the  eggs  in 
his  mouth  and  keeps  them 
there  until  they  are  hatched. 
One  would  think  it  must  be 
difficult  not  to  swallow  them, 
but  he  fasts  all  the  time. 

There  are  many  other 
examples  of  "love"  on  the 
seashore.  The  marine  leech 
or  Skate-sucker  (Pontobdella 
muricata}}  a  warty  green 
animal,  is  both  male  and 
female  at  once,  like  earth- 
worms and  snails.  It  is  a  FlG-  3-— THE  SKATE- 
SUCKER  (PONTOB- 

very  careful  parent,  deposit-     DELLA). 

,  .  .A  Marine  Leech  that 

mg  the  eggs  in  cocoons  in-  Jakes  great  care  of 
side  empty  shells  of  bivalves,  lts  E^s- 
and  mounting  guard  over  them  for  many 
weeks.  It  is  interesting  to  find  examples  of 
marked  parental  care  on  the  lower  rungs  of 
the  ladder  of  life.  One  of  the  humblest  illus- 
trations is  to  be  found  in  a  British  star-fish, 


58  THE  HAUNTS  OF  LIFE 

Asterias  mulleri,  in  which  the  fully  formed 
young  ones,  skipping  the  usual  free-swimming 
stage  in  the  open  water,  are  carried  about  on 
the  mother's  body. 

A  pretty  sight  is  sometimes  seen  if  we  watch 
one  of  the  common  sand-hoppers  (Gammarus 
locusta),  an  Amphipod  crustacean,  flattened 
from  side  to  side,  which  is  always  busy  clean- 
ing up  on  the  shore.  If  we  have  caught  the 
right  kind  and  put  it  in  a  saucer  we  may  see 
quite  a  crowd  of  young  ones  emerging  from 
the  shelter  of  the  mother's  body,  just  like 
chickens  from  under  a  hen.  They  swim 
about  like  miniatures  of  herself,  and  as  she 
slowly  moves  they  follow,  never  venturing  to 
go  farther  than  an  inch  away.  If  we  make  a 
little  splash  in  the  water  in  the  saucer,  they 
hurry  back  below  their  mother,  just  like 
chickens  again.  Looking  at  this  in  a  broad 
way,  through  a  mental  telescope,  we  see  that 
living  creatures  always  answer  back  to  sur- 
rounding difficulties  and  limitations,  and  that 
one  of  the  most  effective  ways  of  answering 
back  is  for  the  parents  to  look  well  after  the 
children.  But  who  wants  "morals"  at  the 
end  of  stories! 


THE  SCHOOL  OF  THE  SHORE          59 

THE  STORY  OF  PALOLO 

Every  autumn,  on  the  shore  at  Samoa,  near 
where  Robert  Louis  Stevenson  used  to  live, 
there  is  what  is  called  a  swarm  of  Palolo. 
Now  Palolo  is  a  green  worm,  whose  proper 
name  is  Eunice  viridis,  and  its  home  is  in  the 
crevices  of  the  coral-reefs.  In  the  fall  of  the 
year  the  body  of  the  worm  becomes  full  of 
germ-cells, — egg-cells  in  the  female  which  de- 
velop into  young  worms,  and  sperm-cells  in 
the  male  which  fertilise  the  eggs.  This  is  of 
course  the  usual  story  with  animals.  Now  in 
October  or  November,  at  the  third  quarter  of 
the  moon,  for  a  short  time  after  midnight, 
the  Palolo  worms  become  very  restless.  They 
back  out  of  the  holes  among  the  corals  and 
writhe  in  the  water.  The  whole  of  the  body 
breaks  off  a  little  way  behind  the  head,  and 
the  headless  bodies  are  so  numerous  in  the 
water  that  it  looks  like  vermicelli  soup.  The 
headless  bodies  burst,  liberating  the  germ- 
cells;  some  of  the  egg-cells  are  fertilised  by 
some  of  the  sperm-cells,  and  a  new  generation 
begins.  The  heads  creep  into  the  crevices  of 
the  coral-reef  and  begin  life  afresh,  growing 
a  new  body.  Thousands  of  the  headless,  wrig- 


60  THE  HAUNTS  OF  LIFE 

gling  bodies  are  washed  on  to  the  sand  by  the 
tides,  and  the  natives  gather  them  in  baskets 
to  make  a  Palolo  feast.  About  the  same  time, 
just  as  if  they  knew,  the  land-crabs  come  down 
to  the  shore,  and  there  is  a  Palolo  feast  for 
them  also.  The  regularity  of  the  swarm  is 
very  interesting — an  inside  change  in  the 
animal  keeping  time  with  an  outside  change 
in  the  seasons — and  it  should  be  noticed  that 
there  are  in  other  parts  of  the  world  other 
kinds  of  Palolo  worms  which  "swarm"  at  a 
different  time  of  year.  The  association  with 
the  moon  is  curious  and  so  is  the  concentra- 
tion to  a  short  time  after  midnight.  The 
wriggling  of  the  headless  bodies  in  the  water 
is  another  very  interesting  point.  But  we  get 
furthest  into  the  heart  of  the  queer  story  when 
we  notice  that  whereas  many  worms  (and 
other  animals,  like  butterflies,  lampreys,  and 
eels)  die  in  giving  rise  to  new  lives,  the 
Palolo-worms  evade  this  penalty.  They  sur- 
render the  greater  part  of  their  body,  but  the 
heads  creep  back  into  the  coral  reefs  and 
begin  again. 


THE  SCHOOL  OF  THE  SHORE    61 

A  GREAT  SCHOOL 

For  a  long  time  after  the  earth  became  a 
home  of  life  there  were  no  animals  on  land  at 
all.  As  far  as  we  can  judge  it  was  in  the  sea 
that  the  first  living  creatures  lived — either  in 
the  open  sea  or  on  the  shore.  Whether  the 
shore  was  the  first  haunt  of  life  or  the  second 
it  is  difficult  to  say,  but  it  is  likely  that  most 
of  the  great  races  of  animals  sojourned  for  a 
long  time  on  the  shore  and,  as  it  were,  served 
their  apprenticeship  there.  Now  on  the  shore 
there  are,  as  we  have  seen,  many  spurs  to  ad- 
venture and  many  outside  changes  that  pro- 
voke changes  in  the  structure  and  constitution 
of  the  animals.  The  shore  is  a  haunt  where 
animals  are  prompted  to  play  all  their  cards, 
to  make  experiments  with  all  their  possibili- 
ties, just  as  we  ourselves  do  when  we  are  in  a 
tight  place.  The  shore  animals  test  all  things 
and  hold  fast  that  which  is  good.  Or,  to  look 
at  it  from  another  side,  the  shore  has  always 
been  a  place  of  sifting,  where  those  creatures 
that  were  not  fit  to  cope  with  the  changeful, 
difficult,  crowded  conditions  have  been  re- 
jected. It  is  in  this  sense  that  we  may  speak  of 
animals  learning  lessons  on  the  seashore:  not 


62  THE  HAUNTS  OF  LIFE 

learning  lessons  as  we  do,  by  getting  ideas  into 
our  head,  but  rather  as  the  races  of  domestic 
dogs  or  horses  have  in  the  course  of  thousands 
of  years  learned  lessons.  Inborn  qualities  that 
were  unsuitable  have  brought  penalties  to  their 
possessors,  and  these  have  been  wiped  out 
from  the  list  of  shore  animals.  Inborn  quali- 
ties that  were  peculiarly  well  fitted  for  shore- 
conditions  have  brought  their  possessors  great 
success,  and  these  possessors  have  survived. 

When  useful  qualities  are  established  in  a 
race  of  animals,  like  docility  in  dogs,  they  are 
not  readily  lost  They  may  be  lost  along  cer- 
tain lines  of  descent,  just  as  pigment  has  been 
lost  in  white  rats  which  are  descendants  of 
the  common  brown  rat,  but  they  are  not  likely 
to  be  lost  altogether.  So  it  is  not  fanciful  to 
suppose  that  qualities,  which  were  established 
among  shore  animals  millions  of  years  ago, 
may  have  enriched  the  inheritance  of  animals 
which  are  now  far  away  from  the  shore,  may 
even  have  enriched  Man's  inheritance.  Those 
in  the  highest  form  of  a  school  may  not  re- 
member that  they  learned  anything  when  they 
were  in  the  junior  school,  though  they  prob- 
ably learned  much! 

But  what  were  the  good  qualities  which  the 


THE  SCHOOL  OF  THE  SHORE          63 

ancestors  of  the  great  races  of  animals  may 
have  had  engrained  in  them  when  they  lived 
very  long  ago  on  the  shore?  They  included 
the  quality  of  holding  tight,  which  leads  on 
to  endurance,  the  quality  of  biding  their  time 
— even  till  the  tide  comes  in — which  leads  on 
to  patience,  the  quality  of  push,  which  leads 
on  to  endeavour,  and  the  quality  of  seizing  a 
good  opportunity,  which  leads  on  to  alertness 
and  power  of  initiative.  These  are  some  of 
the  great  lessons  of  the  old  school  of  the  shore. 


CHAPTER    II 
THE  OPEN  SEA 

Contrast  between  Shore  and  Open  Sea — The  Floating  Sea- 
Meadows — The  Animals  of  the  Open  Sea — Sea-Deserts — 
Swimmers  and  Drifters — The  Whale  as  a  Great  Bundle 
of  Fitnesses — The  Story  of  the  Storm  Petrel — Open-Sea 
Insects  —  Turtles  —  Sea-Snakes  and  Sea-Serpents  —  Fit- 
nesses of  Open-Sea  Drifters — The  Story  of  the  Floating 
Barnacle — Hunger  and  Love  in  the  Open  Sea— The  Open 
Sea  as  a  Nursery. 

T2  Y  the  open  sea,  naturalists  mean  the  well- 

*~*  lighted  surface-waters  well  away  from 
the  shallow  shelf  around  the  islands  and  con- 
tinents. It  is  not  the  mere  surface  of  the 
water,  it  includes  all  the  zones  of  water 
through  which  the  light  penetrates  freely; 
and  that,  we  must  remember,  is  much  farther 
than  at  the  coast  where  the  waves  stir  up  the 
sea-floor  and  bring  so  many  fine  particles  into 
suspension  in  the  water,  that  much  of  the  light 
is  stopped.  In  the  upper  levels  of  the  open 
sea  or  pelagic  haunt,  there  are  multitudinous 
minute  plants  mingled  with  the  animal  ten- 


PLATE  III. — FOUR  OPEN-SEA  ANIMALS. 

The  Portuguese  Man  of  War,  on  the  surface,  with  its  cockscomb-like  red 
float;  the  mother  Argonaut  or  Paper  Nautilus  with  its  cradle-shell, 
made  by  and  embraced  by  two  of  the  arms;  two  Jelly-fishes  below  the 
surface;  and  a  carnivorous  Turtle  pursuing  a  fish. 


THE  OPEN  SEA  65 

ants;  deeper  down  where  the  light  is  less 
abundant  there  are  more  animals  than  plants; 
deeper  still  there  are  animals  only. 

If  the  shore  area  is  the  Great  School  of  life, 
where  animals  have  learned  and  are  still 
learning  many  lessons,  the  open  sea  may  be 
looked  on  as  the  cradle  of  life.  There  are 
many  authorities  who  believe  that  it  was  there 
that  life  had  its  beginnings,  far  back  in  the' 
dim  past.  "There  can  be  little  doubt,"  writes 
one,  "  that  the  pelagic  fauna  antedated  all  the 
faunas  of  the  globe,  and  that  from  it,  through 
a  long  process  of  modification  and  adaptation, 
have  been  derived  the  faunas  of  the  shore, 
the  abyssal  depths,  the  land  surface,  and  the 
fresh  waters." 

But  this  question  of  beginnings  is  too  diffi- 
cult for  us;  we  must  content  ourselves  with 
taking  the  "  pelagic  fauna,"  which  means  sim- 
ply the  animals  of  the  surface  of  the  sea,  as 
we  find  it  now.  But  even  now  we  are  justified 
in  speaking  of  the  open  sea  as  the  cradle  of 
life,  for  many  of  the  animals  which,  in  their 
adult  state,  live  amid  the  turmoil  and  struggle 
of  the  shore,  spend  their  delicate  youth  in  the 
easier  conditions  of  the  open  sea.  The  eggs 
and  larvae  of  some  fishes,  too,  whose  home  is 


66  THE  HAUNTS  OF  LIFE 

on  or  near  the  floor  of  the  sea,  are  found 
floating  at  or  near  the  surface. 


CONTRAST  BETWEEN  SHORE  AND 
OPEN  SEA 

The  shore  waters  pass  gradually  into  the 
open  sea,  and  the  surface  zones  pass  gradually 
into  the  dark,  deep-water  zones,  but  the  haunt 
which  we  call  the  open  sea  has  well-marked 
characters  of  its  own.  It  is  a  place  of  spa- 
ciousness, freedom,  and  plenty.  Let  us  con- 
trast it  with  the  shore  haunt.  There  are 
three  great  differences,  (i)  The  seashore  is 
crowded,  the  open  sea  is  spacious;  there  is 
room  and  to  spare  for  all.  (2)  The  shore  is 
very  changeful,  the  open  sea  is  much  more 
uniform.  The  differences  between  morning 
and  noon,  day  and  night,  summer  and  winter, 
are  less  marked  in  the  open  sea  than  on  the 
shore.  The  open  sea  is  not  indeed  a  place  of 
rest,  for  the  pelagic  animals  swim  or  drift  un- 
ceasingly, and  "know  no  rest  from  birth  till 
death."  But  even  this  movement  often  makes 
things  easier,  for  many  of  them  can  sink  or 
rise  in  the  water,  getting  out  of  the  glare  or  the 
heat,  or  coming  up  to  where  oxygen  is  most 


THE  OPEN  SEA  67 

abundant.  (3)  On  the  shore  there  is  abundant 
food,  but  there  is  a  keen  competition  for  it, 
and  there  is  a  tendency  for  many  of  the  nour- 
ishing particles  in  the  water  to  slip  past  and 
to  sink  down  the  inclined  plane  to  the  deep 
waters.  But  in  the  open  sea  there  is  in  most 
places  great  abundance  of  food,  and  it  is  ac- 
cessible to  all.  So  there  are  three  great  reasons 
why  pelagic  life  is  easier  than  littoral  life. 
It  may  be  objected  that  the  open  sea  is  the 
place  of  storms,  and  it  is  true  that  there  are 
terrible  days  when  sea  and  sky  seem  to  meet 
in  a  welter  of  tumultuous  water.  But  storms 
are  more  dangerous  near  shore  than  in  the 
open  sea  when  there  is  nothing  to  knock 
against,  and  few  of  them  have  a  deep  grip. 
Many  of  the  very  delicate  open-sea  animals, 
like  the  iridescent  and  luminescent  comb- 
bearers  (Ctenophores)  sink  into  quiet  water 
whenever  there  is  a  hint  of  white-horses.  So, 
in  spite  of  storms,  we  may  say  that  in  the  open 
sea  the  barque  of  life  sails  on  an  even  keel.  One 
of  the  disastrous  effects  of  storms  is  seen  where 
one  would  not  at  first  look  for  it,  namely, 
among  some  of  the  open-sea  birds,  like  gan- 
nets.  The  fishes  and  other  creatures  on  which 
they  feed  have  taken  to  deeper  levels  in  the 


68  THE  HAUNTS  OF  LIFE 

water,  which  only  the  deep-divers  can  reach, 
and  if  the  storm  lasts  for  several  days  the  gan- 
nets  and  similar  sea-fowl  begin  to  starve. 
They  become  weak,  and  they  get  battered. 
Perhaps  this  is  part  of  the  explanation  of  the 
fact  that  the  gannet  often  stores  fish  beside  its 
resting-place  on  the  rocky  island. 


THE  FLOATING  SEA-MEADOWS 

If  we  are  to  understand  the  life  of  the  open 
sea  at  all,  we  must  picture  what  Sir  John 
Murray  called  the  "  floating  sea-meadows," — 
vast  tracts  of  water  thickly  peopled  by  minute 
plants,  e.g.  those  Algae  called  Diatoms.  On 
these  everything  else  depends.  For  the 
pelagic  Algae  are  possessed  of  the  chlorophyll 
pigment  that  marks  all  green  plants,  and  they 
are  thus  able  to  utilise  the  energy  of  the  sun- 
light to  build  up  the  simple  materials  of  air, 
water,  and  salts  into  complicated  substances 
like  starch,  on  which  minute  animals  can  feed. 
Of  almost  all  animals  it  must  be  said  that  they 
can  feed  only  on  what  is  living,  or  has  been 
living,  or  has  been  made  by  something  living; 
but  green  plants  feed  on  what  is  not  living — 
air,  water,  and  salts.  Therefore,  in  tracing 


THE  OPEN  SEA  69 

the  circulation  of  matter,  we  must  always  be- 
gin with  the  plants. 

In  most  parts  of  the  sea,  wherever  the  sun- 
light penetrates  and  the  temperature  is  not  too 
low,  there  are  countless  myriads  of  simple 
plants,  "  scattered  like  dust  amid  the  immeas- 
urable water  masses."  These  minute  marine 
Algae  are  not  visible  to  the  naked  eye,  and  it 
is  only  within  comparatively  recent  times  that 
their  abundance,  and  their  great  importance 
in  the  chain  of  life  in  the  ocean,  have  been 
fully  recognised.  Between  Australia  and  New 
Zealand,  we  are  told,  the  officers  of  the  Chal- 
lenger, the  ship  of  the  great  ocean  expedition 
sent  out  by  the  British  Government  in  1873- 
1876,  found  the  water  "continuously  discol- 
oured during  a  period  of  several  days'  sailing, 
and  giving  off  the  odour  of  a  reedy  pond." 
Elsewhere  too,  even  in  the  Arctic  Regions, 
the  water  is  sometimes  "  as  thick  as  soup." 

Along  with  the  minute  Algae  there  are  many 
minute  animals  (Infusorians)  which  have  got 
possession  of  the  green  pigment  chlorophyll, 
and  there  are  others  (Radiolarians)  which 
have  Algae  living  in  partnership  with  them. 
All  these  form  part  of  the  fundamental  food- 
supply  of  the  open  sea.  They  are  eaten  by 


70  THE  HAUNTS  OF  LIFE 

minute  animals,  such  as  the  small  crustaceans 
called  water-fleas,  and  these  may  be  eaten  by 
fishes.  The  bodies  of  dead  animals  are  broken 
down  by  microbes,  and  what  is  not  devoured 
by  other  animals  passes  in  solution  into  the 
sea-water  and  may  be  absorbed  again  as  part 
of  the  food  of  Algae.  The  same  is  true  of  the 
waste-products  voided  from  the  food-canal 
and  kidneys  of  animals.  Nothing  is  ever  lost; 
all  things  flow. 

The  naturalists  at  the  Plymouth  Biological 
Station  have  shown  that  the  abundance  of 
mackerel  in  the  spring  months  depends  on  the 
abundance  of  the  minute  "water-fleas"  or 
copepods  in  the  upper  waters,  and  this  again 
depends  upon  the  abundance  of  minute  Algae 
called  Diatoms  and  of  minute  animals  called 
Peridinid  Infusorians,  which  form  a  great 
part  of  the  "stock"  of  the  sea-soup.  As  the 
multiplication  of  the  Diatoms  and  Infusorians 
in  the  surface  waters  depends  mainly  on  the 
amount  of  sunlight  in  the  early  part  of  the 
year,  we  can  see  a  connection  between  the  sun- 
niness  of  the  spring  and  the  supply  of  mack- 
erel at  Billingsgate.  The  whole  world  is  run 
on  a  plan  of  successive  re-incarnations.  Diatom 
or  Infusorian,  first  link;  copepod  or  water- 


THE  OPEN  SEA  71 

flea,  second  link;  mackerel,  third  link;  man, 
fourth  link;  and  so  the  world  goes  round. 

This  nutritive  chain  is  interesting  in  theory, 
but  it  is  also  very  important  practically,  for 
on  the  abundance  of  the  floating  sea-meadows, 
and  the  population  of  small  animals  which 
these  support,  there  depends,  in  large  meas- 
ure, the  success  of  the  fishing  industry  in 
northern  seas. 

In  addition  to  the  microscopic  plants  there 
are  in  some  places  great  masses  of  drifting 
seaweeds  of  a  higher  order.  They  sometimes 
occur  in  such  enormous  dense  patches  that 
they  impede  the  progress  of  ships  passing 
through  them.  These  seaweeds  do  not  grow 
at  the  surface  but  on  the  sea-floor  in  the  shal- 
low water  region,  and  when  they  are  torn  off 
by  the  waves  they  are  carried  by  currents  far 
out  to  sea.  They  live  for  a  considerable  time 
floating  at  the  surface  with  the  aid  of  their 
numerous  little  bladders,  but  gradually  they 
lose  their  vitality  and  finally  sink  slowly  to  the 
bottom.  New  clumps  are  continually  being 
brought  by  the  same  currents,  so  that  in  some 
parts  of  the  ocean  seaweed  is  always  present. 
The  best  known  of  these  areas  is  the  Sargasso 
Sea  in  the  Atlantic,  and  the  weed  there  har- 


72  THE  HAUNTS  OF  LIFE 

hours  countless  animals  of  many  kinds,  which 
play  hide-and-seek  among  the  fronds. 

It  is  interesting  to  learn  that  the  animals 
that  live  in  the  Sargasso  Sea,  instead  of  being 
predominantly  blue  and  grey,  are  clothed  in 
reds,  browns,  and  dull  greens,  like  the  weed 
among  which  they  hide,  and  they  have  these 
colours  even  when  their  relatives  in  the  open 
sea  are  blue.  Some  of  them  have  the  body 
reddish-brown,  but  the  fins,  which  have  to  be 
spread  out  in  the  open  water,  are  blue.  It  is 
thought  that  the  amount  and  intensity  of  light 
have  a  great  deal  to  do  with  developing  the  dif- 
ferent colours  of  animals  at  different  levels  of 
the  ocean,  but,  whatever  be  the  cause  of  them, 
there  can  be  no  doubt  that  their  effect  is  often 
to  secure  greater  safety  for  their  possessors. 

t        THE  ANIMALS  OF  THE  OPEN  SEA 

Can  we  call  the  roll  for  the  Open  Sea? 
There  are  many  different  kinds  of  Infusorians, 
among  which  there  is  the  world-wide  giant, 
Noctiluca  or  Night-Light,  which  makes  the 
waves  sparkle  in  the  summer  darkness.  A 
giant  indeed,  for  it  is  about  the  size  of  a  pin- 
head.  Many  of  the  chalk-forming  animals  or 


THE  OPEN  SEA  73 

Foraminifers  float  in  the  surface-waters,  and 
this  is  true  of  most  of  the  very  beautiful 
Radiolarians,  which  have  usually  shells  of 
flint,  and  have  established  an  internal  partner- 
ship with  microscopic  Algae.  Perhaps  it  is 
this  partnership  that  has  made  them  so  suc- 
cessful, for  there  are  5000  different  kinds,  and 
the  number  of  individuals  is  past  all  telling. 

The  Stinging  Animals  are  represented  by 
swimming-bells,  most  of  which  are  budded 
off  from  shallow-water  zoophytes;  by  true 
jelly-fishes  or  Medusae,  rhythmically  contract- 
ing and  expanding  their  translucent  discs;  by 
strange  colonies  like  the  Portuguese-Man-of- 
War;  and  by  the  delicate  Ctenophores.  One 
of  these  called  Venus's  girdle,  like  a  ribbon  of 
flexible  glass,  iridescent  and  phosphorescent, 
is  one  of  the  most  beautiful  animals  of  the  sea. 

There  are  not  a  few  open-sea  worms,  some 
of  them,  like  the  Arrow-worm,  quite  trans- 
parent; and  there  are  actually  a  few  sea- 
cucumbers  which  have  departed  widely  from 
the  sluggish  habit  of  their  shallow-water  and 
deep-water  relatives. 

Jointed-footed  Animals  are  represented  by 
many  kinds  of  Crustaceans,  from  gorgeous 
prawns  to  pinhead-like  "water-fleas";  and 


74  THE  HAUNTS  OF  LIFE 

one  must  not  forget  the  family  of  Open-Sea 
Insects. 

Molluscs  are  represented  by  the  Sea-Butter- 
flies and  other  lightly  built  translucent  Gas- 
teropods,  and  by  a  number  of  active  cuttle- 
fishes, such  as  the  Argonaut  and  some  squids. 

Just  across  the  border-line  separating  the 
backboned  from  the  backboneless  animals  is 
the  class  of  sea-squirts  or  Tunicates,  and  it  is 
interesting  to  find  a  few  of  these  in  the  Open 
Sea  which  do  not  degenerate  as  their  shore- 
relatives  do,  but  keep  up  the  promise  of  their 
youth.  Others  form  free-swimming  colonies 
like  the  brilliantly  luminescent  Fire-Flame, 
sometimes  as  long  as  one's  arm,  and  with  a 
light  that  one  can  read  a  few  words  by.  Highly 
fitted  for  open-sea  life  are  the  Salps,  some- 
times like  single  barrels  of  glass,  two  or  three 
inches  long,  sometimes  in  long  chains,  which 
swim  gently  like  glass-serpents  in  the  sea. 

The  rest  of  the  roll  is  easy, — the  open-sea 
fishes  like  the  flying  gurnard,  some  turtles  and 
sea-snakes,  some  birds  like  petrels  and  penguins, 
and  then  the  whales  among  Mammals.  It  is  evi- 
dent that  the  Open  Sea  has  its  share  of  variety. 


THE  OPEN  SEA  75 

SEA-DESERTS 

Some  parts  of  the  Open  Sea  have  only  a  sparse 
floating  population  compared  with  others. 
Most  of  the  Mediterranean  is  poor  when  com- 
pared with  the  North  Sea.  To  the  west  of  Pata-  ' 
gonia  in  the  South  Pacific  there  is  what  may 
be  called  a  sea-desert:  there  are  few  fishes  and 
few  sea-birds;  there  are  almost  no  floating  sea- 
meadows.  On  the  floor  of  the  sea  in  that  region 
there  is  an  unusual  profusion  of  sharks'  teeth 
and  the  ear-bones  of  whales,  which  has  given 
rise  to  the  suggestion  that  these  huge  creatures 
get  into  the  sea-desert  and  die  of  hunger  be- 
fore they  find  their  way  out.  The  teeth  and 
ear-bones  are  so  hard  that  they  can  scarcely  be 
dissolved  in  the  sea;  they  accumulate  on  the 
floor  as  relics  of  ill-fated  visitors  to  the  desert. 

SWIMMERS  AND  DRIFTERS 

The  animals  of  the  open  sea  are  divided  into 
(i)  the  active  swimmers  (technically  making 
up  the  NEKTON)  ;  and  (2)  the  drifters,  or 
easy-going  swimmers  (technically  making  up 
the  PLANKTON).  Good  examples  of  the  ener- 
getic swimmers  are  the  whales,  both  great  and 


76  THE  HAUNTS  OF  LIFE 

small,  the  petrels,  the  sea-snakes,  the  herring 
and  mackerel,  the  flying-fishes,  the  squids,  and 
some  of  the  prawn-like  crustaceans.  The 
drifters  may  be  illustrated  by  the  sea-butter- 
flies (delicately  built  sea-slugs  on  which 
whalebone  whales  largely  feed),  hundreds  of 
kinds  of  small  crustaceans,  numerous  worms 
like  the  transparent  arrow  called  Sagitta,  com- 
plicated colonies  like  the  Portuguese  Man-of- 
War,  and  the  sail-bearers  (Velella),  often 
seen  in  the  Mediterranean  in  beautiful  fleets 
stretching  for  miles.  More  familiar  are  the 
jelly-fishes,,  often  borne  into  shallow  water 
and  left  stranded  in  thousands  on  the  beach. 
These  two  sets  of  animals,  the  swimmers 
and  the  drifters,  are  so  different  that  it  is  bet- 
ter to  study  them  separately.  They  represent, 
so  to  speak,  two  different  attitudes  to  life. 
One  remembers  George  Meredith's  lines: 

"Behold  the  life  of  ease,  it  drifts; 
The  sharpened  life  commands  its  course. 
She  winnows,  winnows  roughly,  sifts 
To  dip  her  chosen  in  her  source. 

Contention  is  the  vital  force 

Whence  pluck  they  brains,  her  prize  of  gifts." 

To  keep  our  ideas  clear  we  must  understand 
that  animals  may  be  tenants  of  the  open  sea 


THE  OPEN  SEA  77 

for  part  of  their  life  and  at  home  elsewhere 
at  another  period.  Thus  the  guillemots  and 
puffins,  which  nest  in  early  summer  in  such 
vast  numbers  on  some  of  the  British  bird- 
cliffs,  are  open-sea  birds  for  a  considerable 
part  of  the  year.  Many  shore  animals,  such 
as  crab  and  rock-lobster,  star-fish  and  sea- 
urchin,  have  free-swimming  larvae  in  the  open 
water,  often  many  miles  from  the  coast.  Jelly- 
fishes  are  characteristically  open-sea  animals, 
their  stranding  on  flat  beaches  being  quite 
accidental,  but  it  should  be  noticed  that  the 
common  and  cosmopolitan  jelly-fish,  Aurelia 
aurita,  passes  through  a  juvenile  fixed  stage, 
attached  to  rock  or  seaweed. 


THE  WHALE  AS  A  GREAT  BUNDLE  OF 
FITNESSES 

The  mammals  of  the  open  sea  are  the 
Cetaceans,  giants  like  the  Right  Whale  and 
the  Sperm  Whale,  and  small  ones  like  dol- 
phins and  porpoises.  All  of  them  have  such 
mastery  of  their  medium  that  they  must  be 
ranked  among  the  conquerors  of  the  open  sea. 
Let  us  think  for  a  little  of  the  whale  as  a 
great  bundle  of  fitnesses,  taking  especially  the 


THE  OPEN  SEA  79 

Greenland  or  "right"  whale,  right  from  the 
whaler's  point  of  view. 

The  whale  is  fish-like  in  shape;  it  has  fore- 
fins  like  a  fish,  and  it  swims  by  means  of  its 
powerful  fish-like  tail.  Yet,  though  we  talk 
of  whale  "  fishery,"  we  all  know  that  a  whale 
is  not  a  fish  but  a  mammal,  that  is,  a  warm- 
blooded animal  that  breathes  by  lungs,  and 
gives  suck  to  its  young.  Naturalists  have  been 
able  to  show,  from  a  study  of  the  whale's  own 
body  and  the  bodies  of  its  fossil  relatives,  that 
the  ancestors  of  the  whale  were  land  mammals, 
and  that,  in  taking  to  the  sea,  they  lost  many 
of  the  old  characters  of  their  race  and  acquired 
others  more  suited  to  their  new  mode  of  life. 

The  body  is  now  fish-like  because  that  is 
the  shape  most  suitable  for  cleaving  the  water; 
the  fore-limbs  are  flippers  or  paddles,  yet 
within  them  "  the  whole  inherited  but  greatly 
shortened  skeleton  of  the  mammalian  forearm 
lies  concealed."  The  hind-limbs  were  no 
longer  of  use,  so  they  disappeared,  but  traces 
of  their  bones  can  still  be  found  hidden  be- 
neath the  blubber;  the  skin  has  lost  its  hair, 
except  for  a  few  very  sensitive  vibrissae  or 
whiskers  about  the  mouth,  but  indications  of 
hair  can  be  seen  in  the  developing  young;  and 


8o  THE  HAUNTS  OF  LIFE 

under  the  skin  there  is  a  thick  layer  of  fat  or 
blubber,  which  serves  the  double  purpose  of 
keeping  the  body  warm  and  lightening  its 
weight  in  proportion  to  its  size. 

The  whale  catches  the  minute  animals  on 
which  it  feeds  by  swimming  with  its  mouth 
open.  But  it  must  be  able  to  breathe  atmos- 
pheric air,  not  air  dissolved  in  water  as  a  fish 
does,  and  the  nostrils,  instead  of  being  on  the 
snout  as  in  other  mammals,  are  far  back  on  the 
forehead,  so  that  breathing  can  go  on  at  the 
same  time  as  swallowing.  In  short,  as  some- 
one has  said,  if  you  took  away  from  the  whale 
all  that  is  adaptation  to  its  mode  of  life  there 
would  be  very  little  of  it  left. 

The  teeth,  when  there  are  any,  have  changed 
in  character,  but  in  the  "right"  whale  they 
disappear  before  birth,  and  have  been  replaced 
by  long  horny  plates  frayed  at  the  ends,  which 
hang  down  into  the  mouth.  There  are  from 
three  to  four  hundred  of  these  plates,  which 
form  the  valuable  "whalebone"  of  commerce. 
The  whale  swims  with  open  mouth  through 
shoals  of  small  animals  like  the  sea-butterflies 
and  water-fleas  we  have  spoken  of,  and  when 
it  has  secured  a  good  mouthful  it  shuts  its  jaws 
and  lets  the  water  trickle  out  at  the  sides  of 


THE  OPEN  SEA  81 

its  mouth,  while  the  whalebone  plates  act  as 
a  sieve  and  prevent  the  small  animals  from 
getting  away.  The  stomach  of  a  dead  whale 
has  been  found  to  contain  a  mass  of  minute 
animals  so  thick  that  it  could  only  be  dug  out 
with  a  spade. 

The  whale  has  no  settled  place  of  abode  in 
the  ocean,  and  its  swimming  powers  enable  it 
to  make  enormous  journeys.  Some  whales 
"  travel  twice  a  year  more  than  a  quarter  of 
the  circumference  of  the  globe,  being  in  sum- 
mer amid  the  Arctic  snows,  and  in  winter  on 
the  other  side  of  the  equator."  They  travel 
mainly  in  the  wake  of  their  food-supply,  but 
as  there  is  a  great  regularity  in  the  occurrence 
of  the  smaller  marine  organisms,  "  their  jour- 
neyings  are  in  general  as  regular  as  if  they 
were  arranged  according  to  the  stars,  and  as  if 
they  took  place  along  laid-out  paths  bounded 
on  both  sides." 

On  their  journeyings  the  whales  often  form 
troops  or  "schools,"  consisting  chiefly  of  fe- 
males and  young  ones.  The  Greenland  whale 
has  usually  only  one  young  one  at  a  time, 
which  may  be  over  three  yards  long  at  birth. 
The  mother  gives  it  suck  for  about  a  year, 
and  is  devotedly  attached  to  it. 


82  THE  HAUNTS  OF  LIFE 

Unfortunately  for  the  whale  man  long  ago 
discovered  the  value  to  himself  of  the  whale- 
bone and  the  blubber,  and  the  chase  of  the 
"right"  whale  has  gone  on  for  centuries. 
Even  its  mother-love  has  been  turned  to  its  dis- 
advantage, for  the  inexperienced  young  one  is 
easily  caught,  and  the  mother  is  absolutely 
careless  of  her  own  safety  in  her  efforts  to  pro- 
tect her  offspring.  Modern  improvements  in 
fishing  vessels  and  apparatus  have  made  the 
warfare  a  very  unequal  one,  and  this  interest- 
ing animal  is  fast  disappearing  from  the  seas. 

THE  STORY  OF  THE  STORM  PETREL 

No  creature  is  more  characteristic  of  the 
Open  Sea  than  the  Storm  Petrel,  for  it  rarely 
touches  land  except  at  the  nesting-time.  From 
the  breeding-places,  such  as  islets  to  the  north 
and  north-west  of  Scotland,  they  migrate  in 
autumn  to  open  waters  and  spend  all  the  win- 
ter there.  One  of  their  many  names,  Mother 
Carey's  Chickens,  suggests  that  they  are  dear 
to  the  Holy  Mother,  who  has  the  weak  and 
storm-tossed  in  her  keeping.  As  to  the  word 
petrel,  it  is  supposed  to  refer  to  St.  Peter's 
attempt  to  walk  on  the  water,  but  it  is  more 


THE  OPEN  SEA  83 

likely  that  it  points  to  the  way  in  which  the 
birds'  feet  go  pitter-pattering  as  they  touch  the 
waves  in  their  flight. 

The  Storm  Petrel  is  a  sooty-black  bird,  with 
a  little  white  about  the  tail  and  under  the 
wings,  just  over  six  inches  in  length,  with  long, 
somewhat  swift-like  wings  well-suited  for 
rapid  flight,  and  with  long  legs,  the  meaning 
of  which  is  obscure.  Its  relationships  are  with 
albatross,  shearwater,  fulmar,  and  the  like,  and 
in  nowise  with  the  gulls.  This  is  shown  by  the 
fact  that  the  horny  bill  is  made  up  of  numerous 
pieces  (taking  our  thoughts  back  to  reptiles' 
scales),  by  the  curious  drawing  out  of  the  two 
nostrils  into  a  double-barrelled  tube,  by  the 
single  chalky-white  egg  with  a  few  reddish- 
brown  spots,  by  the  very  long  sooty-ash  down 
covering  the  nestling,  and  by  many  features 
going  much  deeper. 

The  Storm  Petrel  flies  close  to  the  waves 
with  its  web-feet  touching  now  and  then,  and 
at  other  times  it  paddles  about  on  the  surface. 
Its  food  consists  of  small  fishes,  crustaceans, 
molluscs,  and  other  Open-Sea  animals.  At  the 
nesting-time  it  seems  to  be  fond  of  morsels  of 
sorrel!  The  crop  contains  a  good  deal  of  oil 
which  the  bird  vomits  up  forcibly  when  taken 


84  THE  HAUNTS  OF  LIFE 

by  surprise.  It  is  given  by  both  parents  to  the 
young.  A  captive  Storm  Petrel  was  fed  for 
three  months  on  oil  alone.  The  amount  of  oil 
throughout  the  whole  bird  may  be  inferred 
from  the  fact  that  some  islanders  thread  a  wick 
through  the  dead  body  and  use  it  as  a  lamp, 
"the  excess  of  fat  burning  steadily  until  the 
whole  is  consumed." 

The  Storm  Petrel's  nest  hardly  deserves  the 
name;  it  is  never  more  than  a  little  mattress  of 
dry  grass.  The  single  egg  is  laid  (about  the 
end  of  June  in  Scotland)  in  a  hole  among  the 
rocks  or  among  loose  stones,  or  in  a  burrow, 
which  may  be  a  rabbit's,  or  may  be  partly  made 
by  the  bird's  own  exertions,  though  one  would 
not  think  that  tunnelling  was  much  in  its  line. 
There  is  a  heavy  musky  smell  about  the  hole. 

The  parents  seem  to  share  in  brooding, 
which  lasts  for  about  five  weeks.  During  that 
time  the  birds  are  not  seen  coming  or  going, 
for  they  have  become  twilight  birds,  or  dawn 
and  dusk  birds.  We  suppose  one  parent  sits 
by  day  and  the  other  by  night.  After  the 
young  bird  is  hatched  out,  it  seems  to  be  left 
to  itself  all  the  day  long,  while  the  parents 
collect  oil  for  the  heavy  supper  which  their 
nestling  makes  and  needs.  It  is  not  till  the 


THE  OPEN  SEA  85 

autumn  that  the  young  bird  is  able  to  leave  the 
hole  and  fend  for  itself, — a  very  prolonged 
infancy  which  shows  us  that  the  nesting-place 
must  be  well  hidden.  In  this  connection  it 
should  be  noted  that  the  parents  fly  straight 
into  the  hole  when  they  come  in  from  the  sea 
and  leave  in  the  same  direct  way.  They  are 
sometimes  quite  noisy  as  they  fly  about  at 
night,  but  they  know  the  safety  of  darkness. 
They  come  and  they  go  in  dim  light,  at  dusk 
and  at  dawn.  Most  elusive  birds  I 

There  is  no  doubt  that  the  Storm  Petrel 
belongs  to  a  family  of  ancient  birds,  with  a  long 
pedigree  going  far  back  to  some  kinship  with 
an  extinct,  giant,  toothed  Diver  (Hesperornis 
of  Cretaceous  times).  Like  its  relatives,  such 
as  the  shearwaters,  it  has  held  its  own  by  be- 
coming highly  specialised  in  its  everyday 
habitat  and  also  in  its  way  of  feeding  on  small 
surface  animals  of  the  Open  Sea.  It  is  very 
interesting  to  find  among  its  relatives  a  Diving 
Petrel  (Pelecanoides),  remarkably  but  decep-  ' 
tively  like  a  Little  Auk,  which  has  become  a 
most  expert  diver,  disappearing  instantane- 
ously, swimming  swiftly  with  its  wings  under 
water,  and  emerging  again  in  flight — a  bril- 
liant instance  of  the  way  in  which  survival  is 


86 


THE  HAUNTS  OF  LIFE 


secured  by  trying  every  niche  of  opportunity. 
It  is  the  same  with  the  Storm  Petrel;  it  has 
survived  by  its  originality. 


OPEN-SEA  INSECTS 

A  fine  example  of  what  we  may  call  the 
adventurousness  or  insurgence  of  life  is  to  be 


\  FIG.  5. — SEA-SKIMMER,  HALOBATES. 

An  Insect  that  runs  about  on  the  Open  Sea. 

found  in  the  family  of  sea-skimmers  (Halo- 
batidae),  wingless  insects  that  run  along  the 
surface  of  the  water,  often  a  hundred  miles 
from  land.  They  are  closely  related  to  the 


THE  OPEN  SEA  87 

water-measurers  (Hydrometrida?)  which  we 
see  skating  about  on  the  surface  of  stagnant 
pools  or  even  on  quiet  reaches  of  a  stream, 
but  if  we  had  been  asked  for  the  unlikeliest 
haunt  for  an  insect  we  should  surely  have  said 
the  open  sea  or  the  deep  sea.  The  sea- 
skimmers  appear  to  feed  on  floating  dead 
animals,  and  when  it  is  stormy  they  sink 
below  the  troubled  waters — how,  we  do  not 
know.  Another  interesting  point  is  that  the 
mother  sea-skimmer  has  been  seen  carrying 
her  eggs  about  with  her  after  they  have  been 
laid. 

TURTLES 

Among  the  higher  animals  of  the  open  sea 
must  be  reckoned  some  of  the  turtles;  not  the 
edible  turtle,  perhaps,  for  it  is  a  vegetarian, 
and  must,  therefore,  keep  for  the  most  part  to 
the  shore  haunt,  where  seaweeds  grow,  but  the 
carnivorous  Hawksbill  and  the  Loggerhead — 
the  latter  occasionally  found  on  British  coasts. 
There  is  also  the  rare  Leathery  or  Lyre  Turtle 
of  most  warm  seas,  a  veritable  pelagic  giant. 
Dr.  F.  A.  Lucas,  Director  of  the  American 
Museum  of  Natural  History,  tells  us  that  he 


88  THE  HAUNTS  OF  LIFE 

has  weighed  some  up  to  940  Ib.  and  measured 
some  up  to  7  feet  in  length.  All  these  are 
doubtless  the  descendants  of  land  tortoises, 
for  they  breathe  dry  air  as  terrestrial  animals 
do,  and  they  give  away  their  secret  in  the  fact 
that  they  all  come  to  the  shore  to  lay  their 
eggs  in  the  sand.  Animals  that  have  found  a 
new  kind  of  home  usually  go  back  to  the  old 
home  to  breed.  Whales  evade  this  law  be- 
cause the  mother  carries  her  young  one  for  a 
long  time  before  birth,  so  that  when  it  is  born 
it  can  swim  for  itself. 


SEA-SNAKES  AND  SEA-SERPENTS 

Turtles  have  their  legs  flattened  into  flip- 
pers,— the  oars  by  which  they  swim;  whales 
have  their  fore-limbs  flattened  into  flippers, 
which  are  chiefly  used  in  balancing,  the  pro- 
peller being  the  tail;  snakes  have  no  limbs, 
but  it  is  interesting  to  find  that  the  sea-snakes 
show  a  marked  flattening  in  the  tail  region, 
and  sometimes  in  the  posterior  part  of  the 
trunk  as  well.  In  all  cases  the  meaning  of  the 
flattening  is  the  same;  it  is  an  adaptation 
which  secures  a  good  grip  of  the  water.  The 
sea-snakes  are  mostly  fish-eaters,  and  very 


THE  OPEN  SEA  89 

poisonous;  they  are  common  in  the  Indian 
Ocean;  they  are  of  course  the  descendants 
of  land-snakes,  and,  as  we  have  already 
mentioned,  some  of  them  at  least  come  to  the 
shore  to  bring  forth  their  young. 

The  rock-record  shows  that  there  were  once 
great  sea-serpents,  and  he  is  a  bold  man  who 
says  he  is  sure  there  are  none  living  to-day. 
We  remember  seeing  in  the  Prince  of  Mon- 
aco's collection  a  great  piece  of  a  scaly  cuttle- 
fish. It  came  from  the  stomach  of  a  sperm- 
whale,  but  no  one  has  seen  the  animal.  Un- 
less the  piece  was  a  piece  of  the  very  last  scaly 
cuttlefish,  the  animal  is  likely  to  be  still  repre- 
sented in  the  seas.  Perhaps  there  may  be  a 
giant  sea-serpent  too. 

So  many  of  those  who  go  down  to  the  sea 
in  ships  have  seen  sea-serpents  that  it  is  quite 
a  reasonable  inquiry  to  ask  what  kinds  of  sea- 
serpents  they  saw.  One  species  certainly 
consists  of  the  backs  of  a  row  of  porpoises 
swimming  quickly  and  showing  at  regular 
intervals  on  the  surface.  Another  species 
consists  of  a  long  single-file  of  sea-fowl  flying 
close  to  the  surface.  Another  species  is  one 
of  the  large  sharks,  another  is  certainly  a  large 
cuttle,  and  another  consists  of  the  long  lips 


90  THE  HAUNTS  OF  LIFE 

and  tentacles  of  a  huge  jelly-fish  swaying  near 
the  surface.  Some  jelly-fish  have  a  disc  a  yard 
in  diameter,  and  tentacles  over  30  feet  in 
length. 

Another  sea-serpent  which  our  friend  Mr. 
James  Reid  of  Stonehaven  went  far  to  identify 
is  almost  certainly  the  Oar-fish  or  Ribbon-fish 
(Regalecus),  a  silvery  fish  flattened  like  an 
oar,  sometimes  over  20  feet  in  length.  It  is 
normally  a  deep-water  fish,  but  it  sometimes 
swims  with  an  undulatory  motion  at  the  surface, 
and  may,  when  attacked  by  some  enemy,  raise 
part  of  its  body  several  feet  out  of  the  water. 

FITNESSES  OF  THE  OPEN-SEA  DRIFTERS 

It  is  plain  that  one  of  the  chief  requirements 
of  an  animal  that  lives  in  the  open  sea  is,  that 
it  should  be  able  to  keep  afloat.  This  is  se- 
cured in  many  different  ways.  Thus  there  are 
various  arrangements  for  increasing  the  sur- 
face of  the  body  without  greatly  increasing  the 
weight.  Many  minute  surface  creatures  are 
practically  unsinkable  even  though  their  skele- 
ton is  often  made  of  flint.  Their  armature  is 
produced  into  delicate  processes  or,  in  some 
cases,  stalked  discs  like  half  dumb-bells,  which 


THE  OPEN  SEA 


FIG.  6. — A  REPRESENTATIVE  JELLY-FISH  OF  THE  OPEN  SEA. 

Note  the  four  frilled  Lips  and  the  Tentacles  round  the  Margin  of  the 

Disc. 


92  THE  HAUNTS  OF  LIFE 

give  them  a  big  hold  of  the  water.  Some 
larval  fishes,  like  those  of  the  Angler,  have 
long  flexible  ribbons  floating  out  like  decora- 
tions; and  these  probably  help  in  flotation 
(Fig.  7)- 

Some  of  the  drifters  have  bodies  large  in 
size,  but  with  so  much  sea-water  in  them  that 
they  cannot  sink.  They  have  almost  the  same 
specific  gravity  as  the  water.  If  we  look  into 
the  sea  from  a  boat  we  often  see  the  common 
jelly-fish  (Aurelia)  opening  and  shutting  its 
umbrella  or  disc  a  little  below  the  surface. 
It  looks  quite  large  in  the  water,  and  for  a 
time  after  it  has  been  cast  upon  the  shore 
by  the  tide.  But  a  few  hours  later  it  has" 
shrivelled  up  into  a  very  papery  heap  indeed. 
Its  body  is  made  up  of  more  than  ninety  per 
cent  of  water,  and  when  that  has  evaporated 
there  is  very  little  animal  matter  left.  A  great 
many  drifting  animals  have  this  swollen, 
watery  tissue. 

The  presence  of  fat  or  oil  serves  the  same 
purpose  of  lessening  the  body  weight,  and 
many  of  the  smaller  animals  and  some  pelagic 
eggs  have  this  character  in  common  with  the 
actively  moving  animals  like  the  whales, 
porpoises,  and  many  fishes. 


THE  OPEN  SEA 


94  THE  HAUNTS  OF  LIFE 

Some  of  the  drifters,  instead  of  having  the 
whole  body  made  light,  have  some  special 
part  of  it  adapted  to  serve  the  same  end.  We 
can  best  understand  these  adaptations  if  we 
compare  a  pelagic  animal  with  one  of  its  own 
relatives  which  lives  under  different  condi- 
tions. For  instance,  in  many  parts  of  the  ocean, 
there  are  often  to  be  seen  swarms  of  what  are 
popularly  called  "sea-butterflies,"  or,  not  quite 
so  prettily  but  more  accurately,  "winged 
snails."  These  little  animals  are  Gasteropod 
Molluscs,  and  some  of  them — for  there  are 
many  different  kinds — have  shells,  in  one 
case  spirally  twisted  like  that  of  the  snail. 
But  whatever  be  the  form  of  the  shell  it  is 
always  small  and  light  so  as  not  to  add  much 
weight  to  the  body.  In  place  of  the  fleshy 
walking  "foot"  of  so  many  land  and  shore 
snails  the  sea-butterflies  have  "wings,"  not 
in  the  least  like  those  of  a  butterfly,  but  simply 
outstretched  lobes  or  leaves  of  muscle  which 
buoy  them  up  and  catch  the  wind  so  that 
they  seem  to  be  skimming  lightly  over  the 
surface  of  the  water.  Most  of  the  sea- 
butterflies  inhabit  warm  latitudes,  but  one 
kind,  with  a  shell  no  larger  than  a  pin- 
head,  occurs  in  such  numbers  in  the  Arctic 


THE  OPEN  SEA  95 

seas    that   the    fishermen    call    it    "whale- 
food." 

Sometimes  the  special  device  for  keeping 
afloat  is  just  some  transformation  of,  or  addi- 
tion to,  the  animal's  usual  organs  of  locomo- 
tion. Many  of  the  tiny  crustaceans,  known  as 
copepods  or  "  water  fleas,"  have  on  the  jointed 
legs  that  they  possess,  in  common  with  their 
larger  relatives — lobsters,  shrimps,  and  the 
like — thin  projecting  spines,  each  bearing 
smaller  spines,  all  so  delicate  and  so  much 


FIG.  8. — AN  OPEN-SEA  "WATER  FLEA." 
Showing  Delicate  Processes  which  make  Flotation  easy. 

interlaced  that  the  whole  structure  has  the 
appearance  of  a  feather.  But  that  is  not 
enough  to  keep  the  copepod  afloat;  it  uses 
the  long  antennae  or  feelers  on  its  head  to  give 
a  kind  of  rowing  stroke.  It  does  this  for 


96  THE  HAUNTS  OF  LIFE 

several  successive  strokes,  and  then  stops  for 
a  little.  "  During  the  period  of  rest  the  body 
sinks  slowly,  sometimes  imperceptibly,  but 
never  so  much  that  it  cannot  recover  its 
position  in  the  water  after  the  first  few 
strokes." 

THE  STORY  OF  THE  FLOATING  BARNACLE 

Barnacles  are  strange  crustaceans  which 
give  up  free-swimming  when  they  are  very 
young  and  attach  themselves  to  drifting  logs 
or  the  keels  of  ships.  Even  a  sea-snake  has 
been  seen  with  a  big  bunch  on  its  tail,  and 
some  of  the  unstalked  acorn-shells,  which  are 
second  cousins  of  the  stalked  barnacles,  are 
found  attached  to  the  skin  of  whales. 

The  newly  hatched  barnacle  is  like  the 
newly  hatched  larva  of  many  of  the  lower 
crustaceans.  It  has  a  body  a  little  like  half  a 
pear  cut  lengthwise  and  about  the  size  of  a 
small  pinhead.  It  has  a  median  eye  on  the 
top  of  its  head  and  three  pairs  of  swimming 
appendages.  It  is  called  a  Nauplius,  but  that 
is  neither  here  nor  there.  It  feeds  and  grows 
and  moults,  changing  its  form  into  what  is 
called  a  Cyprid  larva.  This  seems  to  become 


THE  OPEN  SEA  97 

exhausted,  for  it  attaches  itself  by  its  head  to 
a  floating  log,  and  the  front  of  the  head  grows 


FIG.  9. — A  CLUSTER  OF  BARNACLES  (LEPAS  ANATIFERA). 

Hanging  from  a  Floating  Log.     Note  the  Curled  Feet  projecting 

from  the  5-valved  Shell. 

into  a  long  elastic  stalk,  which  bears  the  main 
part   of   the   body   on   its   free   end.      From 


98 


THE  HAUNTS  OF  LIFE 


between  the  five  valves  of  a  shell  that  protects 
the  main  body  of  the  barnacle,  six  pairs  of 
feather-like  limbs  can  be  protruded,  which 
waft  microscopic  organisms  and  particles  into 
the  mouth.  So  much  for  the  ordinary  ship- 


FIG.  10. 

A.  THE    FLOATING    BARNACLE,    with    a 
self-made  Buoy  on  the  Stalk  between 
it  and  a  piece  of  Floating  Seaweed. 

B.  A  COMMON  BARNACLE. 


barnacle,  hundreds  of  which  may  sometimes 
be  found  attached  to  a  log  which  is  tossed  up 
on  the  beach  by  a  storm  after  having  drifted, 
it  may  be,  across  the  Atlantic. 

The  particular  kind  of  barnacle  which  we 


THE  OPEN  SEA  99 

are  calling  the  Floating  Barnacle  (Lepas  fas- 
cicularis)  often  fastens  itself  to  a  small  piece 
of  detached  seaweed — it  may  be  to  a  feather 
or  a  wooden  match.  Its  shell-valves  are  very 
lightly  built,  with  little  lime  in  them,  and  this 
Is  well  suited  for  a  creature  that  fixes  itself  to 
a  light  float.  But  in  spite  of  its  lightness  of 
shell,  the  Floating  Barnacle  often  becomes,  as 
it  grows  bigger,  too  heavy  for  its  float,  and 
begins  to  drag  it  below  the  surface.  What 
then  does  the  creature  do — we  wish  we  un- 
derstood it  better — but  make  a  somewhat  gela- 
tinous, roundish  buoy  containing  bubbles  of 
gas.  This  is  secreted  at  the  lower  end  of  the 
attaching  stalk,  just  above  the  main  body,  and 
the  self-made  buoy  enables  the  barnacle  to  con- 
tinue floating  at  the  surface.  This  is  a  very 
pretty  adaptation  (Fig.  10). 

HUNGER  AND  LOVE  IN  THE  OPEN  SEA 

Hunger  is  much  in  evidence  in  the  open  sea. 
The  baleen  whale  rushes  through  the  water, 
engulfing  countless  open-sea  creatures  in  the 
huge  cavern  of  its  mouth.  They  are  caught 
on  the  frayed  edges  of  the  whalebone  plates 
which  hang  downwards  from  the  palate.  If 


100  THE  HAUNTS  OF  LIFE 

we  look  into  the  mouth  of  a  good-natured 
horse  when  it  yawns  we  see  ridges  crossing 
the  palate;  if  these  ridges  were  to  grow  into 
long  vertical  plates  and  become  horny  they 
would  correspond  to  whalebone  plates.  Every 
now  and  then  the  whale  raises  its  tongue  and 
brushes  a  myriad  of  creatures  towards  the 
back  of  the  mouth,  where  they  are  swallowed. 
It  is  interesting  that  this  giant  should  feed  on 
such  dainty  morsels.  The  reason  why  it  does 
not  drown  as  it  rushes  open-mouthed  through 
the  water  is  that  it  shunts  its  glottis  (the 
entrance  to  the  windpipe)  forward  to  embrace 
the  posterior  end  of  the  nasal  passage,  so  that 
no  water  goes  down  the  wrong  way! 

But  there  is  love  as  well  as  hunger  in  the 
open  sea,  and  no  better  example  could  be  found 
than  the  Paper  Nautilus  or  Argonaut.  This  is 
a  kind  of  cuttlefish  which  floats  on  the  surface, 
and  is  not  to  be  confused  with  the  Pearly 
Nautilus  which  belongs  rather  to  the  shore 
haunt.  The  most  remarkable  thing  about  the 
Argonaut  is  that  the  female  makes,  for  the  pro- 
tection of  its  eggs  and  young  ones,  what  may 
well  be  called  the  most  beautiful  cradle  in  the 
world.  It  is  not  a  house  to  live  in  like  the 
chambered  shell  of  the  Pearly  Nautilus ;  it  is  a 


THE  OPEN  SEA  101 

cradle  made  by  the  female  only.  Moreover, 
the  delicate  cradle  is  made  as  a  secretion  from 
two  of  the  "arms,"  not  as  a  secretion  from 
the  "mantle,"  the  fold  of  skin  which  manu- 
factures the  shell  of  all  other  Molluscs. 

Another  pretty  case  is  the  egg-raft  of  the 
mollusc  called  lanthina.  This  open-sea  Gas- 
teropod  has  a  lightly  built  shell  of  a  fine  violet 
colour,  and  when  the  time  for  egg-laying 
comes  a  bubbly  float  is  made  in  which  the  eggs 
are  embedded,  and  this  is  towed  about  by  the 
parent  as  it  swims. 

THE  OPEN  SEA  AS  A  NURSERY 

Another  big  fact  must  be  included  in  our 
picture  of  the  open  sea — that  it  is  the  nursery 
for  the  young  stages  of  many  shore-animals. 
Delicate  young  stages  which  could  not  survive 
for  an  hour  in  the  rough-and-tumble  condi- 
tions of  the  shore  are  nurtured  safely  in  the 
spaciousness  and  easy-going  uniformity  of  the 
open  sea.  There  is  no  better  example  than  the 
common  Shore-Crab  (Carcinus  mcenas).  The 
developing  eggs  are  carried  about  by  the 
mother  under  the  shelter  of  her  tail.  Out  of 
the  eggs  come  dainty  pinhead-like,  free-swim- 


102  THE  HAUNTS  OF  LIFE 

ming  larvae,  called  zoeas,  marked  by  a  spine 
rising  vertically  above  the  back,  and  by  a  tail 
sticking  out  at  an  angle  to  the  rest  of  the  body. 
These  larvae  are  swept  out  into  the  safety  of 
the  open  water,  and  they  swim  about  near  the 
surface.  They  feed,  they  grow,  they  moult, 
and  another  form  of  larva  results.  This  does 
the  same,  and  a  Megalops  larva  results,  which 
is  beginning  to  be  like  a  crab.  It  has  lost  the 
spine;  it  has  stalked  eyes;  it  has  got  its  full 
complement  of  legs.  Now  this  Megalops 
bends  its  tail  forwards  and  upwards  under- 
neath the  anterior  part  of  the  body  (the 
cephalothorax) ;  it  ceases  to  be  a  free-swim- 
mer; it  sinks  to  the  floor  of  the  sea,  and  creeps 
up  the  slope  to  its  birthplace  on  the  shore — a 
little  crab  about  half  the  size  of  the  nail  of 
our  little  ringer. 

There  is  an  interesting  illustration  of  "  The 
Balance  of  Nature"  in  this  connection.  It 
seems  that  the  shore-waters  are,  on  the  aver- 
age, richer  in  Plankton  than  any  other  waters, 
the  reason  being  that  they  are  always  receiving 
abundant  supplies  of  valuable  salts  brought 
down  from  inland  by  rivers  and  streams.  So 
the  shore-waters  serve  as  a  sort  of  nursery  of 
minute  creatures  that  get  swept  out  to  sea  to 


THE  OPEN  SEA  103 

form  the  "floating  sea-meadows."  Thus  the 
Shore  helps  the  Open  Sea.  On  the  other  hand, 
as  we  have  seen,  there  are  many  shore-animals 
which  depend  upon  the  Open  Sea,  for  it  is  the 
kindly  cradle  of  their  fragile  youth. 


CHAPTER    III 
THE  GREAT  DEEPS 

The  Challenger  Expedition — The  Deep  Deep  Sea — Great 
Pressure — Very  Cold — Very  Dark — Very  Calm  and  Silent 
— Monotony — No  Depth  Limit  to  Life — No  Plants  in  the 
Deep  Sea — No  Rottenness — A  Representative  Fauna — 
Fitnesses  of  Deep-sea  Animals — Puzzle  of  Phosphorescence 
— Big  Eyes  and  Little  Eyes — Origin  of  Deep-sea  Animals 
—Hunger  and  Love  in  the  Deep  Sea— Retrospect. 

TO  our  forefathers  the  depths  of  the  sea 
were  as  unknown  and  as  mysterious  as 
fairyland.  Very  early,  indeed,  fishermen  had 
begun  to  explore  the  surface-waters,  and  had 
forced  them  increasingly  to  contribute  of  their 
abundance  to  their  support,  but  the  life  of  the 
great  depths  was  absolutely  unknown,  though 
imagination  peopled  them  with  strange  forms. 
As  late  as  the  sixteenth  century  a  famous  book 
by  Conrad  Gesner  contained,  mixed  up  with 
illustrations  of  real  animals,  pictures  of  mer- 
men and  mermaidens,  tritons,  dragons,  sea- 
devils,  sea-bishops,  and  other  fabled  monsters. 
104 


PLATE  VII. — THE  FLOOR  OF  THE  DEEP  SEA. 

Showing  a  dredge  being  dragged  along,  three  strange  abyssal  fishes,  a 
graceful  yard-high  Umbellula,  with  a  tassel  of  Polyps  at  the  top  and 
the  base  fixed  in  the  ooze. 


THE  GREAT  DEEPS  105 

By  the  beginning  of  the  nineteenth  century 
imagination  was  being  corrected  by  scientific 
investigation,  and  people  were  becoming  dis- 
inclined to  believe  more  than  they  could  see. 
Apparatus  for  research  was  still  very  imper- 
fect, and  we  find  a  great  English  naturalist, 
Edward  Forbes,  in  1850,  declaring  his  belief 
that  there  are  no  living  animals  below  300 
fathoms.  And  this  in  spite  of  the  fact  that  in 
1818  Sir  John  Ross  dredged  a  Brittle-Star 
(Astrophyton)  from  800  to  1000  fathoms. 

Even  when  animals  were  brought  up  in  the 
net  from  considerable  depths,  it  was  objected 
that  there  could  be  no  certainty  that  these  were 
not  caught  on  the  way  up.  But  that  living 
creatures  existed  at  much  greater  depths  than 
had  been  supposed  was  suddenly  proved  be- 
yond all  doubt  by  an  accident.  A  submarine 
cable  broke,  and  when  the  two  ends  were  fished 
up  for  repair,  they  were  found  encrusted  with 
several  different  kinds  of  animals.  This  dis- 
covery gave  a  great  impetus  to  investigation. 
It  was  too  costly  for  private  enterprise,  but  the 
Governments  of  various  countries,  Britain, 
France,  Norway,  Italy,  and  the  United  States, 
took  the  matter  in  hand,  and  expedition  after 
expedition  was  sent  out,  with  special  equip- 


io6  THE  HAUNTS  OF  LIFE 

ment  for  studying  the  physical  conditions  of 
the  great  depths,  and  obtaining  specimens  of 
the  animals  that  inhabit  them. 


THE  "  CHALLENGER  "  EXPEDITION 

The  first  great  expedition  was  that  of  the 
Challenger  (1872-76),  which  may  be  called  a 
Columbus  voyage,  since  it  practically  discov- 
ered a  New  World — the  world  of  the  Deep 
Sea.  During  three  and  a  half  years  the  Chal- 
lenger circumnavigated  the  globe,  cruising 
over  68,900  nautical  miles.  The  naturalist  in 
charge  was  Sir  Wyville Thomson,  and  the  staff 
included  Mr.  John  Murray  (the  late  Sir  John 
Murray)  and  Mr.  J.  Y.  Buchanan.  Reaching 
down  with  the  long  arm  of  the  dredge,  the  ex- 
plorers raised  treasures  from  over  300  stations. 
The  results  of  this  great  expedition  were  pub- 
lished under  Sir  John  Murray's  editorship  in 
fifty  quarto  volumes.  These  form  the  firm  foun- 
dations of  oceanography — the  science  of  the  sea. 

It  was  at  first  expected  that  many  of  the 
deep-sea  animals  would  be  quite  different  from 
those  living  in  shallower  waters,  and  would  re- 
semble older  types  now  known  only  as  fossils, 
but  with  few  exceptions  this  did  not  prove  to 


THE  GREAT  DEEPS  107 

be  the  case.  The  deep-sea  animals  have  been 
found  on  the  whole  to  be  very  similar  to  others 
of  the  same  families  living  on  the  shore  or  near 
the  shore  elsewhere,  with,  however,  certain 
well-marked  differences,  which  make  them  bet- 
ter fitted  for  life  in  their  actual  surroundings. 

Thanks  to  the  efforts  of  the  different  ex- 
ploring expeditions  and  to  the  published  rec- 
ords of  their  work,  we  have  now  some  very 
definite  ideas  of  the  conditions  of  life  at  the 
bottom  of  the  sea,  and  of  the  ways  in  which 
animals  are  adapted  to  them. 

Every  expedition  that  has  been  sent  out  has 
carried  more  and  more  perfected  apparatus 
for  exploring  the  great  depths.  It  has  been 
found  possible  to  bring  up  specimens  of  the 
lowest  layer  of  the  water,  and  of  the  actual  sea- 
floor  itself,  as  well  as  of  the  animals  that  lived 
there.  Thermometers  have  been  devised  for 
registering  the  temperature,  and  instruments 
for  measuring  the  pressure  at  different  levels. 

THE  DEEP  DEEP  SEA 

By  the  deep  sea  naturalists  mean  practically 
the  floor  of  the  deep  parts  of  the  sea  and  the 
layers  of  dark  water  near  the  floor.  Compara- 


io8  THE  HAUNTS  OF  LIFE 

lively  little  is  known  of  the  vast  zones  between 
the  end  of  the  light's  reach  and  the  floor  of  the 
sea,  so  that,  although  they  are  included  in  the 
idea  of  the  Deep  Sea,  we  may  confine  our- 
selves in  this  study  to  the  floor  of  the  great 
abysses.  This  is  one  of  the  largest  haunts  of 
life,  occupying  about  100  million  square  miles, 
i.e.  more  than  a  half  of  the  whole  earth's  sur- 
face; and  it  is  the  strangest.  It  is  not  difficult 
to  get  comparatively  near  it,  within  a  stone's- 
throw  of  it,  for  we  can  toss  a  pebble  into  it 
from  the  deck  of  a  liner ;  but  no  one  has  ever 
seen  it.  It  is  a  bourne  from  which  no  trav- 
eller can  return.  Yet  we  know  a  great  deal 
about  it,  thanks  to  the  patience  of  explorers. 
The  world  of  the  deep  sea  is  very  deep,  for 
the  average  depth  of  the  ocean  is  2^  miles; 
and,  as  vast  areas  are  comparatively  shallow, 
there  must  be  other  parts  extraordinarily 
deep.  Just  as  the  earth's  crust  has  been 
buckled  into  great  mountains  (the  true  moun- 
tains, not  those  that  are  formed  by  the  unequal 
weathering  of  plateaux) ,  so  it  is  dimpled  down 
into  depressions.  The  very  deep  holes  are 
called  "  deeps " ;  and  the  so-called  "  Challenger 
deep"  in  the  North-West  Pacific  is  nearly  6 
miles  in  depth,  namely,  5269  fathoms.  If  one 


THE  GREAT  DEEPS  109 

could  throw  Mount  Everest  into  this  "deep," 
the  mountain  would  be  swallowed  up,  with 
2600  feet  to  spare.  The  "  Swire  deep,"  off 
Mindanoa,  is  actually  a  little  over  6  miles  in 
depth. 

GREAT  PRESSURE 

In  deep  water  there  is  necessarily  great 
pressure,  because  of  the  immense  weight  of 
water.  At  2500  fathoms  it  is  2^2  tons  on  the 
square  inch — an  unendurable  pressure,  if  it 
were  felt.  It  is  twenty- five  times  greater  than 
the  pressure  exerted  by  the  steam  on  the  pis- 
ton of  our  best  railway  locomotives.  The 
general  reason  why  the  pressure  is  not  felt  is 
that  the  bodies  and  tissues  of  the  animals  are 
permeated  by  the  water.  If  a  ship's  hawser 
is  sunk  to  a  great  depth,  it  is  squeezed  to  less 
than  the  diameter  of  one's  wrist.  If  a  piece 
of  wood  is  weighted  and  sunk  to  a  great 
depth,  it  is  so  much  compressed  that  it  will 
no  longer  float  when  brought  to  the  sur- 
face again.  But  if  a  delicate  glass  vessel  with 
holes  all  over  be  lowered  it  is  not  broken,  for 
the  water  goes  through  and  through  it.  In  a 
general  way,  this  is  true  of  the  deep-sea  ani- 
mals. But  this  is  not  the  whole  truth. 


no  THE  HAUNTS  OF  LIFE 

It  has  happened  repeatedly  that  a  closed 
glass  thermometer  sent  down  inside  a  metal 
tube  has  been  brought  up  again  powdered  to 
a  fine  dust.  In  one  experiment  made  on  board 
the  Challenger,  a  thick  glass  tube  full  of  air 
was  sealed  at  both  ends,  wrapped  in  flannel, 
and  put  inside  a  copper  tube  with  holes  at 
each  end.  This  was  lowered  to  a  depth  of 
2000  fathoms,  and  was  then  drawn  up  again. 
Not  only  was  the  glass  tube  powdered,  but 
the  side  of  the  copper  case  was  crushed  in- 
wards by  the  pressure.  Before  the  empty 
space  caused  by  the  shivering  of  the  glass  tube 
could  be  filled  with  water,  the  side  of  the  cop- 
per case  was  stove  in — an  "  implosion,"  as  one 
of  the  explorers  said,  had  occurred. 

Because  of  the  pressure,  deep-sea  animals 
are  "liable  to  an  accident  to  which  no  other 
animal  in  the  world  is  liable — that  of  tum- 
bling up."  Most  fishes  have  a  silvery  swim- 
bladder  or  air-bladder,  which  contains  gas  and 
enables  the  fish  to  accommodate  itself  to  dif- 
ferent depths.  But  this  accommodation  must 
take  place  very  gradually,  and  if  a  deep-sea 
fish,  in  chasing  its  prey,  rises  too  high  or  too 
suddenly,  its  swim-bladder  expands  so  much 
that  it  cannot  be  controlled  by  the  muscles. 


THE  GREAT  DEEPS  III 

The  fish  is  therefore  unable  to  go  down  to 
the  bottom  again,  but  rises  helplessly,  and 
more  and  more  rapidly,  until  it  reaches  the' 
surface,  usually  dead,  with  its  body  greatly 
distended,  and  sometimes  even  split  open. 


VERY  COLD 

The  deep  sea  is  a  very  cold  haunt,  for  the 
sun's  heat  is  practically  lost  at  about  150 
fathoms;  and  there  is  a  continual  sinking 
down  of  cold  water,  rich  in  oxygen,  from  the 
Poles,  especially  from  the  South.  Throughout 
the  year  there  is  little  variation  in  the  abyssal 
temperature,  which  remains  at  about  28°-34° 
Fahrenheit,  a  little  on  each  side  of  the  freez- 
ing-point of  fresh  water.  Eternal  winter 
reigns.  There  are  cleverly  made  thermome- 
ters for  taking  the  temperature  of  the  abysses ; 
thus,  after  the  well-protected  thermometer 
has  been  down  for  a  while,  a  metal  "  mes- 
senger" is  sent  spinning  down  the  wire,  which 
hits  a  spring  and  turns  the  thermometer  up- 
side down,  so  that  it  cannot  change  on  the  way 
up.  In  a  similar  way  water-bottles  that  collect 
samples  of  the  water  at  various  depths  can 
be  automatically  closed  at  any  point. 


H2      THE  HAUNTS  OF  LIFE 

VERY  DARK 

Very  sensitive  bromogelatine  plates,  auto- 
matically exposed  and  closed  again  at  a  depth 
of  500  fathoms — about  half  a  mile — show  that 
some  rays  of  light  reach  that  depth.  For 
practical  purposes,  however,  it  is  dark  at  250 
fathoms.  Thus  the  deep  sea  is  a  world  of 
dreadful  night,  and  the  utterness  of  the  dark- 
ness must  be  almost  intensified,  one  would 
think,  by  the  fitful  gleams  of  "phosphores- 
cent" light  given  forth  by  various  deep-sea 
animals,  both  sedentary  and  wandering.  Per- 
haps it  is  like  the  very  badly  lighted  suburbs  of 
a  big  town;  perhaps  it  is  like  a  moor  on  a  very 
dark  night,  with  only  a  few  stars  overhead. 

VERY  CALM  AND  SILENT 

The  deep  sea  is  a  place  of  silence  and  calm, 
for  no  sound  can  reach  the  depths,  and  the 
severest  storms  are  comparatively  shallow  in 
their  grip.  There  are  no  swift  currents,  but 
at  most  a  gentle  flow  over  the  beds  of  ooze. 
What  is  this  " ooze"?  Over  vast  tracts  of  the 
ocean-floor  there  is  an  accumulation  of  minute 
particles,  as  fine  as  dust,  varying  in  character 


THE  GREAT  DEEPS  113 

from  place  to  place.  This  is  ooze.  One  kind 
consists  mainly  of  the  beautiful  lime-shells  of 
certain  types  of  chalk-forming  animals  or 
Foraminifera  (Globigerinids)  which  live  on 
the  surface  of  the  sea.  When  these  animals 
are  killed  the  shells  sink  to  form  Globigerina 
deposit,  which  is  very  abundant  on  some  parts 
of  the  floor  of  the  Atlantic.  Similarly  there 
is  Radiolarian  ooze,  consisting  chiefly  of  the 
beautiful  flint-shells  belonging  to  another  set 
of  pelagic  animals.  Pteropod  ooze  consists 
mainly  of  the  remains  of  the  delicate  shells 
of  certain  "sea-butterflies,"  and  Diatom  ooze 
consists  mainly  of  the  siliceous  shells  of  these 
very  simple  pelagic  plants.  Then  there  is 
what  is  called  "  Red  Clay,"  though  it  is 
neither  red  nor  clay,  a  fine  powdery  stuff 
made  by  the  final  disintegration  of  mineral 
materials — all  sorts  of  things  reduced  to  their 
lowest  terms.  In  a  general  way  we  must  think 
of  the  ooze  as  due  to  the  settling  down  of  "  the 
dust  of  the  sea."  In  its  softer  forms  it  has 
been  described  as  "like  butter  in  summer." 
If  there  were  rapid  currents  the  ooze  would 
be  swept  about  and  make  life  impossible,  but 
it  is  well  suited  for  a  world  of  calm.  When 
we  think  of  the  ooze  we  can  readily  under- 


U4  THE  HAUNTS  OF  LIFE 

stand  why  many  of  the  sedentary  abyssal  ani- 
mals, such  as  the  Glass-Rope-Sponge,  are 
fixed  by  long  stalks,  and  why  many  of  the 
wandering  abyssal  animals,  such  as  crabs  and 
sea-spiders,  have  very  lanky  legs,  for  walking 
delicately  on  the  treacherous  surface 

MONOTONY 

The  Deep  Sea  must  be  the  most  monoto- 
nous place  in  the  world.  There  is  no  scenery, 
but  a  succession  of  dreary  undulations  like 
those  of  sand-dunes.  Only  here  and  there  are 
there  ridges  like  water-sheds  or  volcanic  cones 
rising  to  the  surface,  perhaps  to  form  the 
foundations  of  sunlit  coral  islands.  More- 
over, everything  is  so  continuous — eternal 
winter,  eternal  night,  eternal  silence.  What 
an  eerie  picture  this — a  deep,  dark,  cold, 
calm,  silent,  monotonous  world. 

NO  DEPTH-LIMIT  TO  LIFE 

What  of  the  life  of  the  great  deeps?  The 
biggest  fact  is  that  there  is  no  "deep"  too 
deep  for  life.  There  are  more  animals  at  the 
more  moderate  depths;  there  are  more  ani- 


PLATE  VIII. — DEEP  SEA  NEAR  SHORE. 

In  the  shallow  shore  area,  note  Crab,  Star-fish,  Sea  Anemone,  Seaweed. 
In  the  great  depth,  note  a  fish  with  enormous  gape,  a  young  fish  with 
long-stalked  eyes,  two  fixed  Feather-Stars,  an  Umbellula  a  yard  high, 
with  the  base  of  its  stalk  embedded  in  the  ooze. 


THE  GREAT  DEEPS  115 

mals  on  the  lime-ooze  than  on  the  "red-clay" 
mud-ooze;  and  we  do  not  know  much  about 
the  thinly  peopled  miles  of  water  between  the 
limit  of  the  light,  say  half  a  mile  at  the  most, 
and  the  floor  itself.  But  the  big  fact  is  that 
wherever  the  long  arm  of  the  dredge  has 
reached  down  it  has  brought  up  living  crea- 
tures. It  is  astounding  to  read  that  on  the 
"Michael  Sars"  exploration,  the  late  Sir 
John  Murray  and  Dr.  Johan  Hjort  worked  an 
otter-trawl  with  a  spread  of  50  feet  at  a  depth 
of  2820  fathoms,  which  is  over  3  miles! 

NO  PLANTS  IN  THE  DEEP  SEA 

There  are,  of  course,  no  plants  in  the  great 
depths,  except  the  resting-stages  of  a  few  Algae 
that  have  sunk  down  from  the  surface.  We  say, 
"  of  course,"  because  all  ordinary  plants,  pos- 
sessing chlorophyll  (disguised  by  other  colours 
in  many  seaweeds),  require  light  if  they  are 
to  live.  This  raises  an  interesting  question,  for 
if  there  are  no  plants  it  seems  at  first  sight  as 
if  all  the  abyssal  animals  must  be  eating  one 
another,  which  is  absurd,  as  Euclid  used  to 
say.  No  doubt  the  deep-sea  fish  eats  the  deep- 
sea  crustacean,  and  the  deep-sea  crustacean 


n6  THE  HAUNTS  OF  LIFE 

the  deep-sea  worm,  and  the  worm — something 
else ;  but  that  cannot  be  the  whole  story. 

What  then  is  the  basis  of  the  food-supply  of 
the  deep-sea  animals?  The  first  part  of  the 
answer  to  this  question  is,  that  although  there 
are  no  living  plants  there  is  often  plenty  of 
dead  vegetable  matter.  Some  of  this  is 
washed  out  from  the  coastal  belt  and  from 
the  mouths  of  rivers,  for  even  at  great  depths, 
far  away  from  the  coast,  animals  have  been 
fished  up  with  their  stomachs  full  of  remains 
of  sea-grass  and  even  of  terrestrial  plants. 
But  the  greater  part  of  it  comes  from  the  sur- 
face, and  consists  of  the  remains  of  the  minute 
algae  or  marine  plants  which,  as  we  have  seen, 
are  so  abundant  there.  These  minute  parti- 
cles of  vegetable  matter  form  the  food  of 
many  of  the  smaller  deep-sea  creatures. 

Secondly,  we  must  remember  that  dead 
animal  matter  is  continually  sinking  down 
from  the  surface.  This  consists  of  minute 
animals  that  have  been  killed  by  vicissitudes 
of  temperature  and  the  like,  or  of  particles 
from  the  decomposing  bodies  of  surface  ani- 
mals which  have  either  fed  directly  upon 
plants,  or  have  been  able  to  elaborate  their 
own  food  in  the  same  way  as  plants. 


THE  GREAT  DEEPS  117 

In  rare  cases  it  may  be  that  organic  matter 
in  the  water  is  simply  absorbed  by  the  animal's 
body  without  any  direct  "  feeding"  at  all,  or  it 
may  be  wafted  into  the  mouth  by  tentacles  and 
cilia,  or  it  may  simply  sink  into  capacious  open 
mouths,  as  in  the  case  of  abyssal  sea-anemones. 
But  many  of  the  animals  living  on  the  ocean- 
floor  are  "  mud-eaters,"  and  as  the  rich  "  ooze  " 
passes  through  their  food-canal  the  organic 
matter  it  contains  is  digested.  The  same  thing 
happens  in  the  case  of  the  common  earthworm 
as  it  eats  its  way  through  the  soil,  or  in  the 
case  of  the  lobworms  on  the  sandy  beach. 

It  may  be  asked  how  we  know  what  deep- 
sea  animals  eat  since  we  cannot  of  course 
actually  see  what  takes  place  in  the  dark 
abysses.  The  answer  is  that  the  contents  of 
the  food-canal  can  be  studied  in  animals 
dredged  up,  and  also  that  we  can  carefully 
compare  those  that  are  brought  up  in  the 
dredge  with  their  near  relatives  living  under 
different  conditions,  and  try  to  make  out  what 
the  differences  between  them  may  mean. 

Thus  it  is  certain  that  many  of  the  fishes  at 
the  bottom  of  the  sea  are  voracious  flesh-eaters. 
Some  of  them  are  of  the  usual  wedge-shape, 
with  long  tails,  but  a  great  many  are  quite 


n8  THE  HAUNTS  OF  LIFE 

different.  They  have  enormous  heads  with 
strong  jaws  and  teeth,  and  very  large  round 
bodies,  so  that  they  look  as  if  they  were  "  noth- 
ing but  a  mouth  and  a  stomach."  Sometimes 
the  lower  part  of  the  skin  of  the  body  is  so 
loose  that  it  can  stretch  to  an  enormous  extent, 
and  more  than  once  a  fish  has  been  dredged 
up  containing  within  it,  still  undigested,  an- 
other as  big  as,  if  not  bigger,  than  itself! 

Before  we  leave  the  question  of  food,  we 
should  be  clear  in  regard  to  two  things — first, 
that  the  absence  of  living  plants  in  the  Deep 
Sea  is  bound  to  make  the  animal's  struggle  for 
existence  very  keen;  and,  second,  that  what 
count  for  most  are  not  the  bodies  of  big  ani- 
mals that  occasionally  sink  to  the  bottom,  but 
the  minute  creatures  which  are  ceaselessly 
sinking.  It  is  rather  a  pretty  picture — the 
ceaseless  rain  of  dead  animalcules  sinking 
through  the  miles  of  water  like  snowflakes  on 
a  quiet  winter  evening. 


NO  ROTTENNESS 

We  are  accustomed  to  think  of  Bacteria  as 
practically  omnipresent,  playing  many  a  role 
in  the  drama  of  life,  now  helping  and  again 


THE  GREAT  DEEPS  119 

hindering.  There  are  many  Bacteria  in  the 
surface-waters  of  the  sea,  where  they  help  in 
the  circulation  of  matter,  but  there  do  not 
seem  to  be  any  in  the  great  depths.  That 
means  that  there  is  no  rotting,  for  there  is  no 
rotting  without  Bacteria.  If  a  dead  whale 
sinks  to  the  floor  of  the  sea,  with  its  flesh  com- 
pacted together  like  pressed  beef,  it  is  nibbled 
to  fragments  by  crustaceans  and  other  scav- 
engers, and  all  of  it  is  devoured  or  dissolved, 
save  the  cowrie-like  ear-bones  which  are  al- 
most as  hard  as  stone.  But  the  microscopic 
atomies  in  their  never-ending  shower  count 
for  much  more  than  the  carcases  of  whales. 

A  REPRESENTATIVE  FAUNA 

It  is  interesting  to  find  that  the  assemblage 
of  animals  on  the  floor  of  the  Deep  Sea  is  not 
a  picked  one,  but  very  representative.  There 
are  many  simple  microscopic  creatures — 
Foraminifers  and  Radiolarians;  many  horny 
and  flinty  (but  no  calcareous)  sponges;  sea- 
anemones  and  corals;  worms  of  many  kinds 
in  abundance;  star-fishes,  brittle-stars,  sea- 
urchins,  sea-cucumbers,  and  many  sea-lilies; 
numerous  crustaceans  and  quaint  creatures 


120  THE  HAUNTS  OF  LIFE 

called  sea-spiders,  whose  precise  relationships 
are  uncertain;  lamp-shells  and  colonies  re- 
lated to  the  sea-mat;  all  sorts  of  molluscs— 
bivalves,  snails,  and  cuttles;  the  degenerate 
sea-squirts,  some  on  long  stalks;  and  numer- 
ous strange  fishes.  Here  the  list  ends — for 
we  dare  not  include  sea-serpents  in  the  abyssal 
fauna  at  least. 

Walt  Whitman's  famous  picture,  "The 
World  below  the  Brine,"  refers  not  so  much 
to  the  Deep  Sea  as  to  the  bottom  of  the  sea 
within  the  shore-area  in  the  wide  sense.  But 
it  is  incomparably  fine. 

"  Forests  at  the  bottom  of  the  sea,  the  branches  and  leaves, 
Sea-lettuce,  vast  lichens,  strange  flowers  and  seeds,  the  thick 

tangle,  the  openings,   and  the  pink  turf, 
Different   colours,   pale   grey   and   green,    purple,    white,    and 

gold,  the  play  of  the  light  through  the  water, 
Dumb  swimmers  there  among  the  rocks,  coral,  gluten,  grass, 

rushes,  and  the  aliment  of  the  swimmers, 
Sluggish  existences  grazing  there  or  suspended  close  to  the 

bottom, 
Sight  in  these  ocean  depths,  wars,  pursuits,  tribes  breathing 

that  thick-breathing  air,  as  so  many  do." 


FITNESSES  OF  DEEP-SEA  ANIMALS 

Many  of  the  fixed   animals  of  the  great 
depths  have  long  stalks  which  raise  the  im- 


FIG.  ii. — FEATHER-STARS  OR  SEA-LILIES  (CRINOIDS). 
Growing  from  the  Floor  of  the  Deep  Sea. 


122  THE  HAUNTS  OF  LIFE 

portant  part  of  the  body  out  of  the  treacher- 
ous, smothering  ooze.  This  is  very  well  illus- 
trated by  the  sea-lilies  or  Crinoids,  distant 
relatives  of  star-fishes,  which  occur  in  great 
beds  like  daffodils  by  the  lake-side.  Another 
very  good  example  is  to  be  found  in  the 
Umbellulas,  near  relatives  of  the  sea-pens, 
where  the  stalk  is  sometimes  a  yard  long,  and 
bears  at  the  top  a  pendent  cluster  of  polyps, 
often  of  a  beautiful  blue  colour. 

As  intelligible  as  the  long  stalks  of  many 
sedentary  animals  are  the  long  legs  of  many 
of  the  wanderers.  Some  of  the  deep-sea 
prawns  are  the  lankiest  animals  in  existence. 
Some  of  the  sea-spiders  move  about  on  long 
legs  like  stilts.  This  is  well  suited  for  prowl- 
ing about  on  the  surface  of  the  abyssal  ooze. 

Then  there  is  the  exquisite  tactility  of  many. 
In  a  world  of  darkness,  where  sight  counts  for 
little,  touch  becomes  the  important  sense.  Some 
of  the  deep-sea  prawns  have  feelers  several 
times  longer  than  their  body.  One  crustacean 
has  antennae  fully  a  yard  long.  The  deep- 
water  fish  called  Lamprotoxus,  captured  off 
the  west  coast  of  Ireland,  has  a  barbule  several 
times  its  own  length,  and  yet  this  long  probing 
feeler  is  just  an  exaggeration  of  the  little 


THE  GREAT  DEEPS  123 

tactile  organ  seen  hanging  down  for  about  an 
inch  from  the  front  of  the  cod's  lower  jaw. 

Another  fitness  is  the  delicate  build  of  the 
body — such  as  we  see  in  Venus's  Flower 
Basket  (Euplectella),  whose  flinty  skeleton 
rises  like  a  fairy  palace  from  the  floor  of  the 
deep  sea.  When  the  sponge  is  living,  the 
beauty  of  the  skeleton  is  hidden  by  the  tissues, 
and  the  significance  of  the  skeleton  to  the  ani- 
mal is  that  it  forms  a  scaffolding  for  lifting 
a  fairly  big  body — sometimes  about  2  feet 
high — off  the  floor  of  the  sea.  The  scaffold- 
ing is  so  delicate  that  the  weight  of  a  child's 
hand  crushes  it,  and  yet  it  is  more  effective 
than  a  solid  bone  would  be  to  resist  the  enor- 
mous pressure  of  the  water — many  tons  on  the 
square  inch.  It  circumvents  the  pressure,  for 
when  the  water  gets  through  and  through  an 
animal  the  pressure  inside  and  the  pressure 
outside  are  equal.  The  same  applies  to  the 
Glass-Rope-Sponge  (Hyalonema),  which  is 
raised  on  a  long  stalk  of  flint  fibres,  always 
bound  together  by  a  colony  of  anemones.  The 
theory  of  the  adaptation  to  outside  pressure 
becomes  more  difficult  when  we  pass  to  ani- 
mals with  a  body-cavity,  a  food-canal,  blood- 
vessels, and  so  on,  but  the  general  theory  re- 


124  THE  HAUNTS  OF  LIFE 

mains  the  same.  It  is  interesting  to  find  that 
the  bones  of  some  deep-sea  fishes  are  so  lightly 
built  that  one  can  run  a  needle  through  them 
without  breaking  the  point. 

It  is  not  asserted  that  substantial  skeletons 
do  not  likewise  occur  in  the  deep  waters. 
That  is  another  way  of  solving  the  problem, 
which  some  of  the  deep-sea  corals  illustrate. 
But  the  usual  way  out  of  the  difficulty  is  what 
we  have  tried  to  explain:  the  pressure  is  cir- 
cumvented by  making  the  whole  body  very 
permeable. 

PUZZLE  OF  PHOSPHORESCENCE 

While  there  are  many  features  of  deep-sea 
animals  which  we  can  interpret  as  well  fitted 
to  the  peculiar  conditions,  there  are  others 
which  are  puzzling.  One  of  these  is  the  com- 
mon occurrence  of  light-production.  It  is  diffi- 
cult to  get  rid  of  the  word  "  phosphorescence  " 
as  a  name  for  the  light  given  out  by  some  liv- 
ing creatures — both  plants  and  animals.  But 
whatever  be  the  nature  of  the  light  given  out 
by  fire-flies  and  glow-worms,  fire-flames  and 
sea-pens,  it  is  not  phosphorescence.  It  might 
be  called  chemi-luminescence,  for  it  is  a  by- 


THE  GREAT  DEEPS  125 

play  of  certain  chemical  processes  in  which 
oxidation  plays  a  central  part.  Incandescence 
is  light  given  off  under  the  influence  of  great 
heat,  but  animal  luminescence  is  a  "  cold  light " 
with  little  or  nothing  in  the  way  of  heat  rays. 
In  the  cases  which  have  been  most  studied, 
the  boring  bivalve  called  Pholas,  the  lumi- 
nous beetles  called  fire-flies,  and  the  luminous 
water-flea  called  Cypridina,  there  are  always 
two  substances  involved  in  the  animal  light. 
There  is  a  substance  called  luciferin,  which  is 
oxidised,  and  there  is  a  substance  called  luci- 
f erase,  which  acts  on  its  neighbour  like  a  fer- 
ment. Sometimes  the  light  is  given  out  by  a 
stuff  manufactured  in  scattered  or  definitely 
arranged  glands,  and  then  it  may  stream  into 
the  water,  or  the  whole  clammy  surface  of  the 
animal  may  sparkle.  In  other  cases,  the  light 
is  only  seen  inside  special  organs,  the  lumi- 
nous organs,  which  are  of  ten  very  complex  and 
curiously  like  eyes.  It  is  strange  that  organs 
which  produce  light  should  sometimes  show  a 
very  striking  resemblance  to  organs  which  de- 
tect light,  namely,  eyes.  If  you  say  that  it  is 
not  so  very  strange,  for  the  cat's  eyes  shine  in 
the  dark,  you  are  perhaps  not  altogether  wrong, 
for  although  the  shining  of  the  cat's  eyes  is 


126  THE  HAUNTS  OF  LIFE 

just  the  reflection  of  scant  gleams  of  light  and 
is  never  seen  in  total  darkness — when  animal 
light  is  best  seen — there  is  something  quite 
useful  in  the  comparison,  for  the  luminous  or- 
gans have  often  reflectors  not  very  different 
from  the  reflector  in  the  back  of  the  cat's  eye. 

In  any  case,  "animal  light"  is  common  in 
the  deep  sea,  both  in  fixed  and  wandering 
creatures.  The  light-giving  stuff  or  secretion, 
which  remains  luminescent  after  the  animal  is 
dead,  often  oozes  out  on  the  general  surface, 
as  in  sea-pens,  and  may  trail  into  the  water. 
In  its  finer  forms,  in  fishes  and  crustaceans, 
it  shines  out  from  complicated  lanterns,  the 
special  luminous  organs. 

The  Marquis  de  Folin,  who  was  with  one 
of  the  great  French  expeditions,  describes  the 
surprise  and  delight  of  the  naturalists  on 
board  the  exploring  vessel  when  they  first  saw 
a  deep-sea  dredge  brought  up  in  darkness. 
The  dredge  contained  many  coral  animals, 
shrub-like  in  form,  which  threw  off  "flashes 
of  light,  beside  which  the  twenty  torches  used 
for  working  by  were  pale."  Some  of  the  corals 
were  carried  into  the  laboratory,  where  the 
lights  were  put  out.  "There  was  a  moment 
of  magic,  the  most  marvellous  spectacle  that 


Fie.  12. — SEA-PENS  AND  UMBELLULAS. 
Embedded  in  the  Ooze. 


128  THE  HAUNTS  OF  LIFE 

ever  was  given  to  man  to  admire.  Every 
point  of  the  chief  branches  and  twigs  of  the 
coral  Isis  threw  out  brilliant  jets  of  fire,  now 
paling,  now  reviving  again,  to  pass  from 
violet  to  purple,  from  red  to  orange,  from 
bluish  to  different  tones  of  green,  and  some- 
times to  the  white  of  over-heated  iron.  The 
pervading  colour,  however,  was  greenish;  the 
others  appeared  only  in  transient  flashes,  and 
melted  into  the  green  again.  Minute  by 
minute  the  glory  lessened,  as  the  animals  died, 
and  at  the  end  of  a  quarter  of  an  hour  they 
were  all  like  dead  and  withered  branches." 
But  while  they  were  at  their  best  "  one  could 
read  by  their  light  the  finest  print  in  a  news- 
paper at  a  distance  of  6  yards." 

In  the  case  just  described,  the  light  was 
apparently  given  off  from  the  whole  of  the 
living  matter  covering  the  limy  skeleton,  but 
very  often  it  comes  from  particular  spots  or 
"light  organs."  One  cuttlefish  has  about 
twenty  of  these  luminous  spots,  "  like  gleam- 
ing jewels,  ultra-marine,  ruby-red,  sky-blue, 
and  silvery,"  and  another  has  minute  light- 
giving  points  dotted  all  over  its  body. 

Fishes  often  have  these  light-giving  spots, 
and  we  are  told  of  one  fish  which  has  two 


THE  GREAT  DEEPS  129 

large  luminous  plates  just  under  its  eyes.  One 
of  these  gives  off  red  light  and  the  other 
green,  and  from  the  arrangement  of  the  mus- 
cles connected  with  them,  it  is  thought  that 
the  fish  has  control  over  them,  and  can  turn 
on  its  lamps  at  will,  to  warn  off  its  enemies 
or  to  aid  it  in  the  search  for  its  prey! 

"  Very  strange  indeed  would  be  the  appear- 
ance of  these  animals  if  we  could  see  them  in 
the  deep!  In  the  absolute  darkness  of  the 
abyss  they  would  appear  as  ghostly,  silver- 
blue  shapes,  glimmering  like  an  electric  lamp 
through  dense  fog  on  a  dark,  moonless  night. 
Of  all  the  characters  of  deep-sea  fishes  this 
almost  universal  phosphorescence  is  the 
strangest." 

Another  puzzle  may  be  found  in  the  fact 
that  many  deep-sea  animals  are  brightly  col- 
oured. Bright  red  is  common,  for  instance, 
in  crustaceans,  star-fishes,  and  sea-anemones. 
There  is  very  little  in  the  way  of  pattern,  but 
there  is  not  a  little  colour.  What  can  be  the 
meaning  of  colour  in  a  world  of  darkness?  It 
is  highly  probable  that  the  colours  as  such 
have  no  significance  in  the  life  of  these  deep- 
sea  animals,  that  they  are  simply  the  useless 
by-products  of  some  of  the  fundamental  proc- 


130  THE  HAUNTS  OF  LIFE 

esses  that  go  on  in  the  body.  If  this  is  so,  they 
have  their  counterpart  in  the  brilliant  colours 
of  the  withering  leaves  in  autumn.  For  these 
colours,  as  colours,  are  of  no  use  to  the  trees. 

BIG  EYES  AND  LITTLE  EYES 

Another  puzzle  of  the  deep  sea  is  the  occur- 
rence of  fishes  with  big  eyes  and  of  others  with 
little  eyes.  If  the  fishes  were  all  small-eyed 
or  approaching  blindness,  it  would  be  easy  to 
say  that  in  a  world  of  darkness  they  were 
gradually  losing  their  sight,  for  we  know  that 
gold-fishes  kept  in  absolute  darkness  for  three 
years  become  blind,  actually  losing  the  per- 
ceiving elements  called  rods  and  cones  in  the 

.  retina  of  the  eye.  But  what  is  to  be  made  of 
the  occurrence  of  big-eyed  and  small-eyed 
fishes  in  the  same  conditions?  Perhaps  it 
might  be  said  that  the  small-eyed  forms  have 

~been  longest  in  the  abysses,  and  therefore  show 
greater  degeneration  of  the  eye.  But  this 
cannot  be  the  whole  answer,  for  in  many  cases 
the  eyes  are  unnaturally  large — so  large  that 
they  occupy  about  a  fifth  of  each  side  of  the 
head.  Sometimes  they  have  become  what  are 
called  telescope-eyes,  projecting  far  forward 


/ 


THE  GREAT  DEEPS  131 

on  a  cylindrical  stalk,  so  that  they  are  fitted 
for  making  the  most  of  a  dim  light. 

Two  answers  to  the  question  are  possible. 
The  first  is,  that  though  the  animals  with 
large  eyes  have  been  dredged  up  from  the 
great  depths,  and  probably  spend  most  of 
their  time  there,  they  may  sometimes  migrate 
far  enough  upwards  to  come  within  the  sun's 
influence,  and  it  is  only  if  the  eyes  are  never 
used  at  all  that  they  tend  to  dwindle  away. 

The  second  answer  is,  that  though  there  is 
no  daylight,  there  is  some  light  from  lumi- 
nescent animals.  Perhaps  it  is  this  uncertain 
light  which  the  big  eyes  use. 

Perhaps  one  of  the  biggest  puzzles  is  that 
the  ordinary  activities  of  life,  such  as  diges- 
tion and  breathing,  seem  to  go  on  quite 
smoothly  in  the  great  deeps,  although  the 
conditions  of  life  are  so  very  different  from 
those  to  which  the  shallow-water  relatives  of 
the  abyssal  animals  are  accustomed. 

ORIGIN  OF  DEEP-SEA  ANIMALS 

Where  did  the  deep-sea  animals  come  from? 
This  is  a  good  question,  but  we  do  not  yet 
know  enough  to  be  able  to  answer  it  as  we 


132  THE  HAUNTS  OF  LIFE 

should  like.  In  a  general  way  the  answer  is 
that  most  of  the  deep-sea  animals  are  derived 
from  shore-animals  that  migrated  gradually 
— following  the  drifting  food  and  sea-dust — 
down  the  slope  into  the  abysses.  There  are 
no  very  ancient  types  in  the  Deep  Sea;  there 
are  much  more  old-fashioned  creatures  in 
shallow  water.  It  does  not  seem  likely  that 
any  of  the  present-day  deep-sea  animals  were 
established  there  before  the  Triassic  Age. 
Many  are  probably  much  more  recent. 

HUNGER  AND  LOVE  IN  THE  DEEP  SEA 

There  can  be  no  doubt  that  there  is  often 
very  strict  rationing  in  the  Deep  Sea.  This 
is  unmistakably  shown  by  the  enormous  gape 
in  many  of  the  fishes,  by  the  webbing  of  the 
arms  in  some  cuttlefish  to  form  a  capacious 
funnel,  by  the  big,  soft  mouth  of  sea-anemones, 
and  by  many  other  hints  of  hunger. 

But  the  other  note  is  also  sounded.  The 
Challenger  explorers  found  a  sea-cucumber 
with  its  fully  formed  young  ones  attached  to 
the  skin  all  along  the  upper  surface.  There 
are  numerous  expressions  of  a  kind  of  pa- 
rental care  among  brittle-stars,  especially  in 


THE  GREAT  DEEPS  133 

the  Antarctic.  The  male  sea-spiders  from 
the  deep  sea,  like  those  from  shallow  seas, 
carry  the  bunches  of  eggs  attached  to  their 
limbs.  It  is  also  interesting  to  find  that  some 
animals,  whose  seashore  representatives  lib- 
erate eggs,  bring  forth  embryos  in  the  Deep 
Sea.  This  is  probably  an  adaptation  which 
counteracts  the  risk  of  the  passive  eggs  being 
smothered  in  ooze. 

RETROSPECT 

Let  us  now  gather  together  briefly  what  we 
have  learned,  and  try  to  make  a  mind-picture 
of  the  depths  of  the  ocean. 

The  average  depth  is  2^  miles,  but  there 
are  "  deeps "  of  over  6  miles,  so  that  the 
highest  mountain  in  the  world,  if  thrown 
in,  would  be  far  below  the  surface  of  the 
water. 

It  is  very  cold;  it  is  absolutely  soundless; 
it  is  calm,  and  quite  dark,  save  for  the  weird 
blue-green  light  radiating  from  the  corals 
fixed  in  the  mud,  or  from  the  luminous  spots 
of  the  animals  slowly  moving  in  and  out 
among  these  "  perpetual  light-houses."  Star- 
fishes, sea-urchins,  sea-cucumbers,  many  kinds 


134  THE  HAUNTS  OF  LIFE 

of  molluscs,  many  worms,  and  hosts  of  other 
animals  lie  buried  in  the  mud,  or  creep  or 
wriggle  slowly  over  it.  Crabs,  lobsters,  and 
prawns  with  long  legs  and  long  feelers  prowl 
about  hunting  for  their  food;  great,  many- 
armed  cuttlefishes  dart  hither  and  thither,  and 
fishes  with  gaping  mouths  and  cruel-looking 
teeth  swim  very  leisurely,  for  their  bones  are 
spongy  and  their  muscles  soft,  perhaps  be- 
cause in  these  still  waters  there  has  never 
been  any  need  for  great  exertion. 

Life  is  most  abundant  at  a  depth  of  about 
2000  fathoms,  and  it  varies  in  richness  ac- 
cording to  the  character  of  the  ooze.  But  no 
locality  and  no  depth  has  yet  been  discovered 
which  does  not  harbour  living  animals  of 
some  kind. 

Verily,  if  modern  scientific  research  has  de- 
prived us  of  our  mermaidens  and  our  sea- 
king's  palaces,  it  has  given  us  no  unfair  ex- 
change in  revealing  to  us  this  eerie,  cold, 
dark,  still  world  below  the  waters. 

Not  the  least  of  our  gains  is  this,  the  dem- 
onstration that  there  are  no  slums  in  Nature. 
In  these  inaccessible  haunts,  in  this  world 
of  darkness,  there  is  the  same  order,  the  same 
fitness,  the  same  finished  perfection,  the  same 


THE  GREAT  DEEPS  135 

beauty  that  we  find  elsewhere.     As  William 

Watson  has  well  said: 

/ 

"  Nay,  what  is  nature's 

Self,  but  an  endless 

Strife  towards  music, 

Euphony,  rhyme? 

Trees  in  their  blooming, 
Tides  in  their  flowing, 
Stars  in  their  circling, 
Tremble  with  song. 

God  on  His  throne  is 
Eldest  of  poets; 
Unto  His  measures 
Moveth  the  whole." 


CHAPTER    IV 
THE  FRESH  WATERS 

Variety  of  the  Fresh  Waters — Similar  Animals  in  widely  sep- 
arated Places — From  Salt  Water  to  Fresh — Origin  of 
Fresh-water  Animals — Circulation  of  Matter  in  the  Fresh 
Waters — The  Web  of  Life  in  the  Fresh  Waters — The  Dan- 
ger of  Drought — The  Danger  of  Frost — The  Danger  of 
Flood — Parental  Care  among  Fresh-water  Animals — The 
Story  of  the  Eel — The  Story  of  the  Salmon — The  Story  of 
the  Lamprey — Water  Insects — The  Story  of  the  Fresh- 
water Spider. 

THE  fresh  waters  do  not  occupy  even  a 
hundredth  part  of  the  earth's  surface — 
1,800,000  square  miles  out  of  the  197,000,000, 
which  form  the  total.  But  the  haunt  makes 
up  for  its  relatively  small  size  by  its  great 
variety. 


VARIETY  OF  THE  FRESH  WATERS 

There  are  lakes  so  vast  that  their  depths  may 

be  as  cold,  and  dark,  and  plantless  as  those  of 

the  sea  itself.   Lake  Baikal  in  Asia  has  a  depth 

of  760  fathoms,  with  an  additional  atmosphere 

136 


THE  FRESH  WATERS  137 

of  pressure  for  every  5  fathoms,  and  there  are 
seals  in  its  waters.  There  are  shallow  ponds 
of  all  sizes  which  vary  greatly  in  temperature 
from  day  to  night,  and  from  season  to  season. 
They  may  bear  a  foot  of  ice  in  the  depths  of 
winter,  and  be  dried  up  altogether  in  the  heat 
of  summer.  Yet  year  after  year  these  shallow 
ponds  show  an  abundance  of  life.  It  may  be 
noticed  that  the  strict  difference  between  a 
pond  and  a  lake  is  not  in  size,  for  a  pond  may 
be  a  mile  long,  but  in  depth,  for  a  true  pond 
is  always  shallow.  Then  there  are  the  lonely 
mountain  tarns  with  their  dark,  mysterious 
waters  and  a  rather  sparse  animal  population ; 
there  are  great  rivers  and  purling  brooks, 
swift  torrents  and  sluggish  streams  with  little 
fall ;  there  are  marshes  grading  into  the  shore, 
and  others  passing  insensibly  into  dry  land. 
There  are  also  artificial  fresh  waters,  as  in 
canal  and  quarryhole.  There  is  a  consider- 
able fauna  in  the  water-supply  of  some  cities. 


SIMILAR  ANIMALS  IN  WIDELY 
SEPARATED  PLACES 

A  striking  feature  about  the  fresh-water  ani- 
mals is  that  they  are  often  the  same  or  nearly 


138  THE  HAUNTS  OF  LIFE 

the  same  in  widely  separated  basins.  A  lake 
in  the  Scottish  Highlands,  one  of  the  thou- 
sand lakes  of  Finland,  a  lake  in  Japan,  may 
have  similar  tenants.  Why  is  this?  It  is  partly 
because  water-birds  carry  the  same  small  ani- 
mals on  their  feet,  or  in  clodlets  on  their  feet, 
from  one  lakeside  to  another,  because  the 
wind  sometimes  does  the  same,  and  because 
changes  in  the  surface-relief  of  the  earth's 
crust  not  only  make  valleys  separate  from  one 
another,  but  bring  them  together  again.  But 
the  most  important  reason  is  probably  that  the 
animals  which  colonised  the  fresh  waters  came 
for  the  most  part  from  the  shore,  and  that  only 
certain  kinds  of  constitution  could  stand  the 
change.  Let  us  think  for  a  little  what  the 
change  from  the  shore  to  the  fresh  waters 
would  mean,  always  bearing  in  mind  that  it 
would  be  a  very  slow  and  not  a  sudden 
change,  for  most  salt-water  animals  die  im- 
mediately if  they  are  put  into  fresh  water. 

FROM  SALT  WATER  TO  FRESH 

What  characters  or  qualifications  were 
necessary  before  the  transition  from  salt 
water  to  fresh  water  could  be  even  attempted? 


THE  FRESH  WATERS  139 

The  first  and  most  important  of  these  was 
the  power  to  endure  slight  changes  in  the 
degree  of  saltness.  This  power  would  be 
found  most  frequently  in  animals  that  lived 
'in  the  shore  area,  for  there  such  changes 
occur  very  often.  Heavy  rain  falling  into  the 
smaller  pools  may  make  them  comparatively 
fresh,  and  will  also  affect  the  shallow  water 
of  the  sea  itself,  though  not  to  the  same  de- 
gree. About  the  mouths  of  streams  and 
rivers,  too,  the  water  is  fresher  than  else- 
where, and  the  tides  carry  up  so  much  salt 
water  that  the  estuaries  are  salt,  or  at  least 
brackish,  for  a  long  way  up,  and  only  very 
gradually  become  quite  fresh. 

It  was,  therefore,  probably  by  this  route 
that  the  rivers  and  lakes  got  a  great  part  of 
their  inhabitants.  We  can  easily  picture  some 
of  the  more  adventurous  of  the  shore  animals 
making  their  way  slowly  up  the  river  mouths 
until — not  in  a  single  lifetime,  let  us  remem- 
ber, but  in  the  course  of  many  generations — 
they  got  beyond  the  influence  of  the  tide  alto- 
gether, and  settled  down  in  fresh  water. 

The  move  seems  to  have  been  so  successful, 
in  some  cases  at  least,  that  the  enterprising 
colonists  increased  abundantly,  and  some  of 


1 40  THE  HAUNTS  OF  LIFE 

them  have  survived  even  though  all  their 
nearest  relatives  in  the  sea  have  disappeared. 
Others  again,  after  long,  long  ages,  seem 
never  to  have  become  quite  at  home  in  fresh 
water,  but  have  to  go  back  periodically  to 
their  original  home  in  the  sea  to  deposit  their 
eggs,  so  that  the  change  from  salt  water  to 
fresh  has  to  be  made  by  every  individual  in 
its  own  lifetime.  The  eel  is  one  of  these,  and 
its  life-story  is  so  interesting  that  we  shall  fol- 
low it  in  detail  later  on. 

Another  qualification  necessary  for  migrating 
up  the  rivers  was  one  which  nearly  all  fresh- 
water animals  must  possess — the  power  of  en- 
during considerable  changes  of  temperature. 
This  power,  too,  would  most  frequently  be 
found  among  the  shore  animals,  for,  as  we  have 
seen,  those  living  in  the  open  sea  have  only  to 
sink  beneath  the  surface  to  protect  themselves 
from  sudden  changes,  while  in  the  deep  sea  the 
temperature  remains  always  about  the  same. 

ORIGIN  OF  FRESH-WATER  ANIMALS 

But  there  is  a  previous  question:  Why  do 
we  think  that  fresh-water  animals  must  have 
come  from  the  sea?  May  they  not  have  begun 


PLATE  IX. — A  FRESH-WATER  POOL. 

Showing  Trout,  Minnow,  Crayfish,  Fresh-Water  Mussel,  a  little  Crus- 
tacean called  Gammarus,  a  young  Dragon-fly  creeping  on  the  reeds, 
Adult  Dragon-fly,  and  Mayflies  in  the  air. 


THE  FRESH  WATERS  141 

to  be  where  they  are  now?  To  answer  this 
very  reasonable  question  briefly  is  not  possible, 
but  part  of  the  answer  may  be  given.  Among 
the  first  animals  to  have  bodies — namely,  the 
Sponges — we  find  one  family  in  the  fresh 
waters,  and  all  the  rest — including  many  hun- 
dreds of  different  kinds — in  the  sea.  That  is 
a  straw  which  shows  how  the  wind  blew. 
Among  the  Stinging  Animals  which  come 
next  in  order — the  sea-anemones  and  corals, 
the  jelly-fishes  and  zoophytes — only  about  half 
a  dozen  are  found  in  the  fresh  waters ;  all  the 
rest — thousands  of  different  kinds — live  in  the 
sea.  So  in  many  other  cases,  and  the  home  of 
the  great  majority  of  any  great  race  of  animals 
is  likely  to  be  the  original  home  of  the  race. 

Another  step  in  the  argument  is  the  Natural 
History  rule  that  when  an  animal  has  more 
than  one  habitat  in  the  course  of  its  life-history, 
the  one  in  which  it  starts  another  generation,  or 
begins  its  own  life,  is  usually  the  original  home. 

The  robber-crab  wanders  far  from  the  shore 
and  even  climbs  the  hills,  but  it  goes  back  to 
the  seashore  every  year  to  spawn,  and  there  is 
no  doubt  at  all  that  it  was  originally  a  shore 
animal.  So  the  fresh-water  eel  goes  to  the  deep 
sea  to  spawn,  and  there  is  almost  no  doubt  that 


142  THE  HAUNTS  OF  LIFE 

its  ancestors  were  deep-water  fishes.  Similarly, 
though  the  flounder  is  often  found  in  rivers 
20  miles  from  the  sea,  it  does  not  spawn  in 
fresh  water,  it  must  go  back  to  its  old  home  in 
the  shallow  sea.  It  will  be  interesting  to  think 
out  some  cases  that  seem  to  break  this  rule. 

It  is  also  to  be  remembered  that  some  ani- 
mals are  at  present  making  the  transition  from 
salt  water  to  fresh.  The  flounder  is  a  case  in 
point,  undoubtedly  a  marine  fish,  but  be- 
coming more  and  more  accustomed  to  the 
rivers.  The  quaint  Manatee,  included  with 
the  Dugong  in  the  small  order  of  mammals, 
known  as  sea-cows,  or  Sirenia,  is  typically  a 
coastal  mammal,  but  it  goes  far  up  the  rivers, 
and  it  is  now  found,  for  instance,  in  the  Ever- 
glades of  Florida,  a  far  cry  from  the  sea. 

In  any  case  we  should  not  think  of  the 
fresh-water  fauna  as  a  fixed  and  finished  as- 
semblage of  animals.  It  is  a  noteworthy  fact 
that  many  fresh-water  animals  spend  only  a 
part  of  their  lives  in  the  fresh  water.  Some 
of  these  seem  to  be  still  in  process  of  accus- 
toming themselves  to  it,  others  to  be  leaving 
it  for  salt  water,  and  others  again  are  appar- 
ently on  the  way  to  becoming  land  animals. 

How  can  we  tell  in  which  direction  a  par- 


THE  FRESH  WATERS  143 

ticular  form  is  tending — whether  it  is  be- 
coming more  of  a  fresh-water  animal  or  less? 
The  process  of  change  in  an  animal  race  may 
go  on  so  very  slowly  that  at  a  given  point  we 
cannot  detect  it  at  all.  But  that  is  not  to  say 
that  it  is  not  taking  place.  It  has  been  said 
that  if  a  clock  could  be  invented  that  would 
go  so  slowly  that  it  would  only  tick  once  in 
thirty  years,  we  should  not  believe  that  it  was 
going  at  all.  Yet  even  that  rate  is  fast  com- 
pared with  the  rate  at  which  Nature  works 
out  some  of  her  wonderful  changes. 

But  though  we  may  not  hope  to  detect  Na- 
ture actually  at  work,  there  are  various  ways 
by  which  those  who  study  her  closely  can  trace 
out  some  of  the  changes  that  have  taken,  and 
are  still  taking,  place.  One  of  these  is  by 
comparing  one  kind  of  animal  with  another 
closely  related  to  it,  and  trying  to  make  out 
the  meaning  of  the  differences  between  them. 
Sometimes  so  many  kinds  of  animals,  with 
only  slight  differences  between  each  kind,  are 
found  that  they  can  be  arranged  in  a  regular 
series,  and  it  is  possible  to  be  fairly  certain  of 
the  path  along  which  the  race  has  travelled. 

Another  way  is  by  studying  the  growth  of 
a  particular  animal  from  the  time  that  it  be- 


I44  THE  HAUNTS  OF  LIFE 

gins  to  form  within  the  egg.  For  every  ani- 
mal in  its  early  life  tends  in  a  greater  or  less 
degree  to  repeat  in  its  personal  history  some 
of  the  stages  that  have  been  gone  through  in 
the  history  of  its  race,  and  much  of  this  can 
be  made  out  by  a  careful  study  of  the  stages 
that  appear,  often  to  disappear  again  very 
quickly,  in  the  earlier  period  of  the  building 
up  of  the  body  of  the  individual. 

The  same  thing  is  true  to  some  extent  of 
habits,  and,  in  particular,  many  animals  have 
an  impulse  to  go  back  at  the  breeding-season 
to  bring  forth  their  young  in  the  place  where 
they  themselves  first  began  life.  Therefore, 
when  we  find  an  animal  leaving  the  haunt  in 
which  the  greater  part  of  its  life  is  passed, 
to  bring  forth  its  young  in  quite  a  different 
one,  we  have  good  grounds  for  believing  that 
its  ancestors  once  had  their  home  in  the  haunt 
to  which  it  returns. 

But  there  is  a  difficulty  here  which  must  be 
faced.  There  are  some  cases  in  which  the 
youthful  stages  are  passed  in  a  haunt  which 
was  certainly  not  the  original  headquarters.  A 
good  illustration  of  this  may  be  found  in  in- 
sects like  May-flies  and  Dragon-flies,  Caddis- 
flies  and  Alder-flies,  Gnats  and  Harlequin- 


THE  FRESH  WATERS  145 

flies,  whose  larvae  live  in  the  fresh  waters.  But 
no  one  can  suppose  that  these  insects,  or  any 
insects,  had  their  original  home  in  water.  The 
explanation  is  that  when  an  animal  lives  in  a 
haunt  full  of  dangers  for  the  young,  it  has  often 
circumvented  the  difficulty  by  rinding  another 
haunt  for  the  juvenile  stages.  The  aquatic 
larvae  of  insects  are  not  old  fashioned;  they 
show  new-fashioned  fitnesses  to  a  haunt  which 
is  really  rather  foreign  to  the  insect's  nature. 


CIRCULATION  OF  MATTER  IN  THE 
FRESH  WATERS 

To  understand  the  animal  life  of  a  lake  or 
pond  we  must  as  usual  start  with  the  plants. 
For  the  plants,  which  are  able  to  feed  upon 
the  not-living,  supply  food  for  the  animals 
which  feed  upon  the  living,  or  what  has  been 
living,  or  what  has  been  made  by  something 
living.  There  are  many  fresh-water  plants 
growing  round  the  margin,  like  bog-bean, 
mare's  tail,  iris,  and  bullrush;  others,  like 
water-lilies,  are  rooted  at  a  considerable  depth, 
and  send  their  leaves  and  flowers  on  long 
stalks  up  to  the  surface;  others,  like  duck- 
weed, with  roots,  and  bladderwort,  without 


146  THE  HAUNTS  OF  LIFE 

roots,  float  freely.  Now  there  are  animals  that 
browse  on  these  plants,  and  other  animals  that 
thrive  on  the  broken-down  fragments  of  these 
plants,  when  they  decay.  But  important  as 
these  big  plants  are,  they  are  not  so  funda- 
mental as  the  immense  number  of  simple 
plants  that  float  in  the  surface-waters — the 


FIG.  13. — BLACKBOARD  DRAWING  OF  CIRCULATION  OF 

MATTER. 

Bacteria  break  down  the  Mud  and  Manure;  the  results 
and  the  Bacteria  are  eaten  by  Infusorians;  these  are 
devoured  by  Water-fleas,  and  these  by  Fishes,  and 
a  higher  incarnation  is  in  Man. 

fresh-water  Algae.  These  often  make  the  water 
like  green  soup ;  and  there  are  often  far  more 
of  them  in  a  pitcher  than  we  can  see  of  stars 
on  a  frosty  night.  It  is  on  them  that  the  econ- 
omy of  the  pond  or  lake  mainly  depends. 


THE  FRESH  WATERS  147 

These  minute  plants  are  the  chief  producers 
in  the  fresh-water  community.  The  animals 
are  the  consumers,  though  many  of  them  de- 
vour their  smaller  neighbours,  who  might 
therefore  rank  among  the  producers.  When 
an  animal  dies  in  the  water,  the  Bacteria 
which  cause  all  rotting  break  down  its  body 
into  salts  and  gases.  The  salts,  sooner  or  later, 
often  with  the  help  of  other  Bacteria,  become 
the  food  of  aquatic  plants,  and  the  gases  pass 
into  the  air  or  are  captured  in  the  water  be- 
fore they  get  so  far.  Thus  the  Bacteria  are 
the  middlemen. 

The  experiment  has  been  made  of  putting 
mud  and  manure  in  boxes  round  the  edge  of  a 
fish-pond,  which  tended  to  "give  out"  pe- 
riodically, apparently  because  the  water  was 
too  sparsely  peopled.  Bacteria  worked  at  the 
material  in  the  boxes  and  made  it  available 
for  the  microscopic  animals,  called  Infuso- 
rians,  which  always  abound  where  there  is 
rotting  organic  matter.  The  Infusorians  de- 
voured what  the  Bacteria  prepared,  and  some 
of  them  devoured  the  Bacteria  too.  A  living 
cataract  of  Infusorians  fell  into  the  pond  and 
formed  the  food  of  water-fleas  or  Copepods, 
which  in  turn  were  eaten  by  fishes.  What  was 


148  THE  HAUNTS  OF  LIFE 

part  and  parcel  of  the  mud  and  manure  be- 
came, through  the  middlemen  Bacteria,  part 
and  parcel  of  the  Infusorians.  These  were  in- 
corporated in  water-fleas,  which,  in  turn, 
found  a  new  incarnation  in  fishes.  What  was 
part  and  parcel  of  the  fish  became  part  and 
parcel  of  man.  And  so  the  world  goes  round. 
If  we  believe  that  fish-food  is  good  for  the 
brain,  as  some  doctors  tell  us,  we  may  trace 
the  links  of  a  chain  between  mud  and  clear 
thinking. 

The  sturdy  fern,  called  Bracken,  is  doing 
much  harm  in  Britain  and  other  countries  by 
destroying  pasture  land.  It  kills  out  the  grass 
and  other  useful  plants,  and  it  is  so  vigorous 
that  it  can  conquer  even  the  heather.  One 
wishes,  therefore,  that  there  might  be  a  whole- 
sale repetition  of  the  experiment  of  tumbling 
cartloads  of  bracken  into  fresh-water  lochs. 
The  result,  where  it  was  tried,  was  the  great 
improvement  of  the  fishing.  For  the  bracken 
tumbled  into  the  water  was  acted  on  by  Bac- 
teria, and  rotted,  providing  food  for  Infuso- 
rians, which  in  turn  gave  sustenance  to  water- 
fleas,  as  these  to  fishes.  If  we  cast  bracken  on 
the  waters,  we  may  get,  after  many  days — 
not  bread  exactly,  but  trout! 


THE  FRESH  WATERS  149 

THE  WEB  OF  LIFE  IN  THE  FRESH 
WATERS 

Nowhere  do  we  find  better  examples  of  the 
web  of  life  than  in  the  fresh  waters,  meaning 
by  the  web  of  life  the  linkages  between  living 
creatures,  binding  them  together.  Here  are 
some  examples. 

The  eggs  of  the  common  salt-water  mussel  are 
wafted  out  into  the  sea  and  develop  into  free- 
swimming  larvae,  which  eventually  settle  down ; 
but  the  eggs  of  the  fresh-water  mussel  are  re- 
tained inside  the  shell  and  develop  in  a  special 
brood-chamber,  the  cavity  of  the  basket-work- 
like  outer  gill.  They  develop  into  tiny  pinhead- 
like  larva?,  called  Glochidia,  each  with  two 
valves  toothed  at  the  margin.  The  eggs  are  pro- 
duced about  midsummer  in  Britain,  but  the 
Glochidia  are  not  allowed  to  escape  till  early 
in  the  following  year.  They  are  not  allowed  to 
escape  unless  a  fish,  such  as  a  minnow,  comes 
swimming  slowly  past.  Then  the  mother- 
mussel  allows  some  of  her  offspring  to  escape, 
and  they  come  crowding  out,  like  boys  set  free 
from  school,  clapping  their  valves  in  the  water 
and  exuding  delicate  gluey  threads.  Some  of 
them  are  lucky  enough  to  get  attached  to  the 


150  THE  HAUNTS  OF  LIFE 

skin  of  the  minnow;  the  others  perish.  The 
Glochidia  are  somehow  attuned  to  answer 
back  to  minnow,  and  if  we  have  some  in  a 
soup-plate  they  become  greatly  excited  if  a  lit- 
tle piece  of  dead  minnow  is  dropped  into  their 
midst.  In  some  North  American  fresh-water 
mussels  it  is  to  one  kind  of  fish,  and  to  that 
alone,  that  the  larvae  respond.  So  subtly  inter- 
laced are  the  threads  of  the  web  of  life.  But 
returning  to  our  own  rivers  and  ponds,  we  find 
that  the  Glochidia  remain  for  a  considerable 
time  on  their  bearer,  the  minnow,  burrowing 
a  little  way  into  the  flesh,  and  undergoing  a 
great  change  in  the  architecture  of  their  body. 
When  the  great  change  or  metamorphosis  is 
accomplished,  they  drop  off  into  the  mud  and 
start  an  independent  life  as  young  fresh-water 
mussels,  often  far  from  the  place  where  they 
were  born.  We  understand  then  that  the  fresh- 
water mussel  cannot  continue  its  race  unless 
there  is  this  strange  linkage  with  a  minnow. 
And  just  as  the  mussel  is  linked  to  a  fish,  so 
there  is  a  fish  which  is  linked  to  the  mussel. 
For  the  Bitterling,  Rhodeus  amarus,  which 
lives  in  some  continental  rivers,  has  a  long 
egg-laying  tube  with  which  the  eggs  are  ac- 
tually injected  into  the  fresh-water  mussel. 


THE  FRESH  WATERS  151 

The  eggs  develop  in  the  gill-chamber,  and  the 
larval  fishes  spend  some  time  there  before 
they  find  their  way  out. 

Another  linkage  of  the  fresh-water  mussel  is 
in  connection  with  pearls,  for  some  of  the  pearls 
are  due  to  the  larval  stages  of  parasitic  worms 
— allied  to  the  liver-flukes — the  adults  of  which 
live  inside  aquatic  birds.  When  the  micro- 
scopic parasite  settles  down  in  the  skin-fold  or 
mantle  of  the  mussel,  it  is  smothered  in  layer 
after  layer  of  translucent  lime,  mingled  with  a 
little  organic  matter,  and  the  result  is — a  pearl. 

The  pied-wagtail,  so  often  seen  curtseying  on 
the  stones  by  the  side  of  the  stream,  is  linked 
to  successful  sheep-farming,  for  it  is  very  fond 
of  the  little  water-snail  (Limncea  truncatula) 
which  harbours  the  juvenile  stages  of  liver- 
fluke,  which  often  causes  fatal  liver- rot  in  sheep. 

Some  authorities  say  that  the  decline  of 
Greece  was  partly  due  to  the  introduction  of 
malaria.  If  this  be  so,  we  may  link  the  decline 
of  Greece  to  the  mosquito  which  harbours  and 
spreads  the  microscopic  animal  that  causes 
malaria  in  man.  The  malaria-organism,  Plas- 
modium  by  name,  is  imbibed  along  with  the 
blood  when  the  mosquito  bites  a  malaria  pa- 
tient; it  goes  through  Complicated  changes 


152 


THE  HAUNTS  OF  LIFE 


FIG.  14. — LIFE-HISTORY  OF  GNAT  OR  MOSQUITO. 
i.  Raft  of  Eggs.     2.  Newly  hatched  Larvae.     3   and  4.  Larger 
Larvae  breathing  by  the  Tail-trumpet  at  the  Surface.     5   and 
6.  Pupae,   with   Breathing-tubes  on   Head.     7.  Winged    Insect 
emerging  from  Pupa-case  and  flying  away. 


THE  FRESH  WATERS  153 

within  the  mosquito  and  multiplies  there ;  when 
the  mosquito  bites  another  man  it  infects  him 
with  the  malaria  germs  of  which  it  is  the  car- 
rier. Pouring  a  little  paraffin  on  stagnant  pools 
so  alters  the  nature  of  the  surface  film  that  the 
larval  mosquito,  which  lives  in  the  water,  can 
no  longer  hold  on  to  it  with  its  breathing-tube, 
and  dies  for  lack  of  oxygen.  Moreover,  as  there 
are  little  fishes  that  greedily  devour  the  larvae 
of  mosquitoes,  and  are  very  useful  in  water- 
tanks  where  the  use  of  paraffin  is  impossible, 
we  may  actually  link  little  fishes  to  the  decline 
of  Greece.  "  Ye  gods  and  little  fishes ! " 

THE  DANGER  OF  DROUGHT 

Life  in  fresh  waters  has  its  peculiar  difficul- 
ties, and  the  three  greatest  are:  DROUGHT, 
FROST,  and  FLOODS.  Especially  in  warm  coun- 
tries is  there  great  risk  of  the  pool  drying  up. 
Little  wonder  then  that  many  fresh-water  ani- 
mals have  learned  to  lie  low  in  a  state  of  latent 
life.  Some  small  crustaceans  have  been  known 
to  lie  for  forty  years  in  dried  mud,  without 
losing  the  power  of  actively  living  when  the 
mud  was  moistened  again.  A  naturalist  visit-  ''• 
ing  Jerusalem  took  a  little  mud  from  the  pool 


154  THE  HAUNTS  OF  LIFE 

of  Gihon,  at  the  Jaffa  Gate,  and  put  it  in  a  pill- 
box. It  lay  dry  for  forty  years,  but,  when 
some  of  the  dry  dust  was  then  put  into  a  saucer 
full  of  water,  it  gave  rise  after  a  short  time  to 
some  lively  water-fleas.  Their  resting-eggs  had 
retained  their  vitality  for  longer  than  an  aver- 
age human  lifetime.  This  explains  why  pools, 
which  have  been  dry  for  several  years,  are 
found  teeming  with  little  creatures  soon  after 
they  have  been  once  more  filled  with  water. 
The  power  of  lying  low  in  the  mud  also  helps 
us  to  understand  what  we  considered  already, 
that  similar  fresh-water  animals  often  occur 
in  widely  separated  basins.  For  mud  may  be 
transported  for  long  distances  in  various  ways, 
e.g.  on  the  coats  of  cattle,  and  on  the  feet  of 
birds.  When  the  caked  mud  is  dissolved  off 
in  the  water,  the  minute  animals  may  become 
lively  again,  or  sometimes  it  seems  to  be  their 
well-protected  eggs  that  have  survived. 

In  tropical  Africa  there  is  a  strange  fish 
which  has  lungs  as  well  as  gills.  It  is  known 
as  the  "  mud-fish  "  because,  when  the  water  of 
the  lake  in  which  it  lives  gets  very  low,  it  bur- 
rows down  into  the  mud,  and  works  itself 
round  and  round  until  it  has  formed  a  com- 
plete mud-casing  round  its  body.  This  dries 


THE  FRESH  WATERS  155 

and  hardens,  and  the  fish  lies  safely  within  it 
until  the  rainy  season  comes,  and  the  lake  is 
once  more  filled  with  water.  Specimens  have 
been  brought  to  this  country  within  their  mud- 
nests,  and  they  sometimes  come  out  all  right, 
even  after  they  have  been  out  of  the  water  for 
nine  months.  A  fish  out  of  water  indeed! 


FIG.  15. — THE  QUEENSLAND  MUD-FISH  (NEOCERATODUS). 
Breathing  by  Lungs  as  -well  as  by  Gills. 


THE  DANGER  OF  FROST 

In  many  parts  of  the  world  one  of  the  se- 
verest trials  of  life  is  the  freezing  of  the  water. 
Even  a  resourceful  animal,  like  an  otter,  may 
be  starved,  because  the  water  is  frozen,  or  it 
may  venture  through  a  hole  in  the  ice  and  fail 
to  find  its  way  back  again.  Many  small  fresh- 
water animals  die  altogether  in  the  winter, 
and  only  their  eggs  live  on,  protected  within 
hard  envelopes.  The  fresh-water  sponge  on 
the  stones  of  the  river  and  lake  dies  away,  and 
in  the  late  autumn  it  looks  as  if  it  were  rot- 


156  THE  HAUNTS  OF  LIFE 

ten.  But  it  does  not  wholly  die.  Pinhead-like 
clumps  of  cells,  called  gemmules,  protected 
within  a  sphere  of  beautiful  capstan-like 
spicules  of  flint  are  formed  throughout  the 
dying  body  of  the  sponge,  and  these  rest 
through  the  winter  and  start  new  sponges  in 
the  spring.  It  is  interesting  to  compare  this 
partial  dying  with  what  happens  to  the  float- 
ing bladderwort,  and  to  some  other  water- 
plants.  The  bulk  of  the  plant  dies,  but  the 
end  of  each  shoot,  heavily  laden  with  stores  of 
starch,  breaks  off  and  sinks  to  the  floor  of  the 
lake,  rising  again,  lightened,  in  spring,  to 
start  a  new  floating  plant. 

Of  great  importance  for  living  creatures  is 
a  peculiar  property  of  water — almost  a  unique 
property.  It  has  its  maximum  density — that 
is  to  say,  is  most  closely  packed  together — at 
4  degrees  centigrade.  When  it  cools  below 
this,  towards  freezing,  it  expands,  instead  of 
contracting  as  almost  all  other  substances  do 
when  they  pass  from  a  liquid  to  a  solid  state. 
The  expansion  of  the  freezing  water  means 
that  the  water  at  the  bottom  of  the  pond  rises 
to  the  surface  as  it  cools  below  4  degrees  centi- 
grade, and  there  forms  a  protective  floating 
blanket  of  ice.  As  more  freezing  water  rises 


THE  FRESH  WATERS  157 

the  blanket  of  ice  thickens,  and  this  tends  to 
prevent  the  water  of  the  pond  from  becoming 
colder  and  colder  and  eventually  solidifying. 
For  eighty-five  days  in  the  year — the  winter 
season — the  warmer  water  of  the  fresh-water 
basin  is  at  the  bottom;  the  pool  does  not  be- 
come solid  ice,  except  in  very  rare  cases ;  the 
fresh-water  animals  are  able  to  continue  year 
in,  year  out,  and  from  this  many  consequences 
flow. 

THE  DANGER  OF  FLOOD 

Another  great  risk — in  streams,  especially 
— is  that  of  being  washed  down  to  the  sea,  or 
carried  out  into  a  flood-bed  and  left  high  and 
dry,  or  in  stagnancy.  We  can  understand, 
then,  why  many  fresh-water  animals,  such  as 
brook-leeches  and  insect-larvae,  have  gripping 
organs  or  suckers  which  anchor  them. 

But  another  method  of  circumventing  the 
danger  of  being  washed  away  is  to  shorten 
down  the  juvenile  stages  of  the  life-history, 
when  the  risks  are  greatest.  It  is  useful  to  think 
of  an  animal's  life-history  as  a  whole — egg, 
embryo,  larva  (if  there  is  such  a  stage),  young 
creature,  adolescent  animal,  full-grown  ani- 
mal, ageing  animal,  and  to  think  of  it  as  a  band, 


158  THE  HAUNTS  OF  LIFE 

parts  of  which  are  elastic,  so  that  they  can  be 
stretched  out  further  or  shortened  down.  Thus 
some  animals  have  a  very  long  embryo  period 
(like  Peripatus),  others  a  very  long  larval  pe- 
riod (like  May-flies),  others  a  long  childhood 
(like  kittens),  others  a  long  maturity  (like 
horses) .  When  it  is  necessary,  a  part  of  the  life- 
curve  can  be,  as  it  were,  stretched  out  in  the 
course  of  generations — man  is  stretching  out 
his  youthful  period — and  another  part  can  be 
shortened  down.  Many  fresh-water  animals 
have  shortened  down  the  riskful  juvenile 
period. 

A  clear  example  of  what  we  mean  may  be 
found  in  the  fresh-water  crayfish.  It  is  as  high 
up  the  genealogical  tree  as  the  lobster,  and 
almost  as  high  up  as  the  crab.  But  while  the 
shore-crab  has  a  long  life-history,  sketched  in 
our  study  of  the  seashore,  with  one  larval  stage 
after  another,  the  young  of  the  fresh-water  cray- 
fish is  hatched  as  a  miniature  of  its  parent.  It 
is  practically  identical  with  its  parents,  except 
that  the  tips  of  its  claws  are  bent  in,  the  better 
for  gripping  the  empty  egg-shells  which  are 
glued  to  the  swimmerets  of  the  mother.  It  has 
no  larval  stages  to  pass  through;  it  remains  in 
shelter  under  its  mother's  tail  until  it  is  able  to 


PLATE  X. — A  FRESH-WATER  POOL. 

Showing  on  the  surface  Water-Lilies,  Duckweed,  some  insects  (Water- 
Measurers)  gliding  on  the  surface,  a  Water-Snail  gliding  back  down- 
wards below  the  surface-film.  Below  may  be  seen  a  Crested  Newt, 
two  Water-beetles  (Dytiscus),  a  Water-Spider  and  her  dome-like 
Web;  also  a  Sponge  growing  on  the  bulrush. 


THE  FRESH  WATERS  159 

fend  for  itself.  Indeed,  the  young  crayfishes 
that  have  begun  to  swim  about  often  seek  the 
shelter  of  the  mother's  tail,  as  chickens  the  hen's 
wings.  This  shortening  down  of  the  chapters 
of  the  life-history  is  an  adaptation  that  tends 
to  circumvent  some  of  the  dangers  of  youth. 
The  time  taken  to  grow  up  may  vary  even 
among  the  same  animals  according  to  the  sea- 
son, and  may  be  very  different  in  two  closely 
related  species.  There  occurs  throughout  Cen- 
tral Europe  a  larger  cousin  of  our  common 
newt,  known  as  the  "fire-salamander,"  from 
the  large  splashes  of  orange  colour  on  its  black 
body.  It  brings  forth  its  young  alive,  but  still 
surrounded  by  the  egg  envelope,  which  bursts 
at  once,  setting  free  a  gill-bearing  tadpole. 
This  little  creature  does  not  take  on  the  sala- 
mander form,  or  leave  the  water  until  it  is 
about  three  and  a  half  months  old.  But  if  the 
summer  is  dry,  and  the  water  in  the  pools  gets 
low,  the  stages  are  gone  through  more  rap- 
idly, and  development  may  be  complete  at  the 
end  of  two  months.  This  salamander  is  not 
found  at  a  greater  height  than  2500  feet. 
Above  that  its  place  is  taken  by  another  very 
similar  form  without  the  orange  spots,  known 
as  the  black  salamander.  This  form  may 


i6o  THE  HAUNTS  OF  LIFE 

occur  up  to  a  height  of  9000  feet,  where  it  is 
above  the  region  of  pools  and  quiet  brooks, 
and  no  water  is  available,  except  the  cold, 
swift  mountain  streams,  in  which  tadpoles 
could  not  live  or  find  food.  The  black  sala- 
mander, therefore,  does  not  go  through  a  tad- 
pole stage  at  all;  the  young  are  miniature 
copies  of  the  parent  at  birth.  Moreover,  there 
are  never  more  than  two  of  them,  while  the 
salamander  of  the  plains  may  produce  as 


FIG.  16. — THE  SPOTTED  SALAMANDER   (SALAMANDRA  MACULOSA). 
From  a  Specimen.    The  Natural  Size  is  about  5  inches. 

many  as  seventy  tadpoles  in  a  season.  For 
the  pools  of  the  plains  are  full  of  hungry  little 
fishes,  newts,  water-beetles,  and  their  greedy 
larvae,  and  a  hundred  other  carnivorous  crea- 
tures. So  there  must  be  tadpoles  enough  to 
ensure  that  some  at  least  will  survive  and 
carry  on  the  race.  The  mountain  salamander, 
born  fully  formed,  and  able,  like  its  parent, 
to  hide  among  damp  leaves  and  in  holes  in  the 
ground,  has  not  nearly  so  many  risks  to  run. 


THE  FRESH  WATERS  161 

PARENTAL  CARE  AMONG  FRESH-WATER 
ANIMALS 

The  common  little  Bullhead,  or  Miller's 
Thumb,  has  also  to  take  precautions  against 
having  its  eggs  washed  away  or  damaged  by 
running  water.  This  little  fish  is  regarded 
with  some  awe  by  country  children,  because 
it  apparently  utters  a  cry  when  it  is  caught 
and  taken  out  of  the  water.  But  the  "cry  "is  no 
more  produced  by  vocal  organs  than  is  the 
buzzing  of  the  bee,  or  the  chirping  of  the  grass- 
hopper. The  bullhead,  in  common  with  a 
good  many  other  fishes,  has  the  habit  of 
supplementing  its  gill-breathing  by  coming  to 
the  surface  and  swallowing  a  mouthful  of  air, 
and  it  is  the  sudden  rush  of  this  air  out  of  its 
body  that  causes  the  sound.  The  bullhead 
lives  a  solitary  life,  usually  hidden  among  the 
stones  at  the  bottom  of  a  rapid  stream.  It 
scoops  out  a  nest  beneath  a  stone,  to  the  under- 
side of  which  it  fastens  its  cluster  of  eggs. 
Unlike  the  lampreys,  which  show  no  care  for 
their  eggs  after  they  have  been  deposited, 
the  male  bullhead  remains  on  guard  over  the 
eggs  and  young  fry  for  about  a  month.  Then 
the  family  breaks  up,  and  the  young  ones  seek 


1 62  THE  HAUNTS  OF  LIFE 

out  solitary  places  in  which  to  hide  during  the 
two  years  that  must  pass  before  they  become 
mature,  and  are  ready  to  look  for  a  mate. 

Even  more  interesting  in  its  habits  is  the 
common  three-spined  stickleback,  and,  in  its 
case  also,  it  is  the  father,  not  the  mother,  that 
shows  parental  care.  The  male  stickleback 
constructs  a  barrel-shaped  nest  of  parts  of 
water-weeds,  glued  together  with  a  sticky  sub- 
stance from  its  own  body.  This  nest  is  open  at 
one  end,  and  may  be  either  on  the  ground  or 
attached  to  water-plants.  When  it  is  ready, 
the  stickleback  goes  off  in  search  of  a  mate, 
and  escorts  her  "with  evident  pleasure"  to  the 
nest.  After  depositing  her  eggs,  the  female 
fish  makes  her  escape  by  the  simple  method  of 
breaking  a  hole  in  the  nest,  usually  at  the  side. 
Another  and  another  female  is  brought  till  the 
nest  is  sufficiently  full.  Then  the  proud  father 
sets  himself  to  watch  over  the  eggs,  keeping 
them  clean,  and  fiercely  driving  away  all  in- 
truders. When  the  young  fry  hatch  out,  his 
labours  are  by  no  means  over;  indeed,  they  are 
more  arduous  than  ever,  for  he  tries  to  keep  his 
numerous  children  safely  at  home  as  long  as 
possible,  but  as  fast  as  he  drives  them  in  at  the 
front  door  they  wriggle  out  again  at  the  back! 


THE  FRESH  WATERS  163 

The  stickleback's  sharp  spines  and  fighting 
temper  protect  him  from  larger  enemies,  for 
even  a  pike  hesitates  about  swallowing  so 
prickly  a  creature.  But  his  curiosity  is  often 
the  undoing  of  him,  for  he  will  snap  at  the 
most  unlikely  bait,  even  when  food  is  abun- 
dant. Their  numbers  are  kept  down  by  man, 
because  of  the  damage  they  do  in  eating  the 
eggs  of  the  trout 

THE  STORY  OF  THE  EEL 

Although  the  common  eel  (Anguilla  vul- 
garis)  is  not  wholly  a  fresh-water  animal,  it 
spends  most  of  its  life  in  this  haunt,  and  this 
is  the  best  place  for  discussing  its  extraor- 
dinary life-history. 

If  we  are  on  the  look-out  beside  any  of  our 
larger  rivers  during  April  and  May,  we  may 
have  the  good  fortune  to  see  the  "  eel-fare,"  as 
it  is  called.  Thousands  upon  thousands  of 
tiny  "  elvers,"  about  2^/2  inches  long,  and  the 
thickness  of  a  bone  knitting-needle,  are  mak- 
ing their  way  from  the  sea  up  the  rivers. 
They  keep  close  to  the  banks  at  each  side  and 
form  an  unbroken  procession  that  may  take 
many  days  to  pass  a  particular  spot.  They 


1 64  THE  HAUNTS  OF  LIFE 

travel  only  in  sunlight,  and  a  passing  cloud 
will  cause  them  all  to  disappear  like  a  flash, 
but  when  the  sun  shines  out  again  they  swim 
steadily  on  their  way. 

It  used  to  be  the  custom  in  some  places  to 
catch  these  little  creatures  in  baskets,  to  use 
them  for  bait,  or  even  to  fry  them  in  cakes. 
But  in  other  places  it  is  realised  that  this  is  a 
short-sighted  policy,  since  the  full-grown  eels 
are  much  more  valuable  as  food.  Instead, 
therefore,  of  trapping  the  elvers,  people  some- 
times hang  ropes  of  straw  over  the  rocky 
places  to  help  them  on  their  way  up  the  river. 

From  the  rivers  the  elvers  push  on  into  the 
smaller  streams  and  people  the  ponds  and 
lakes  connected  with  them.  If  the  water  or 
the  food-supply  in  one  pond  gets  low,  they 
have  no  difficulty  in  finding  another,  for,  un- 
like most  fishes,  they  are  able  to  live  for  a 
considerable  time  out  of  water,  and  they  have 
a  way  of  wriggling  themselves  through  damp 
grass  for  quite  considerable  distances.  One 
naturalist  tells  us  that  he  kept  two  small  eels 
for  a  time  in  an  aquarium,  and  "they  passed 
most  of  the  day  buried  in  the  sand  at  the  bot- 
tom, but  night  after  night  they  made  their 
escape  and  were  always  found  in  the  morning 


THE  FRESH  WATERS  165 

at  the  other  side  of  the  room,  apparently 
dead;  however,  when  returned  to  the  water 
they  swam  about  apparently  none  the  worse 
for  their  excursion."  Once  settled  down  in 
suitable  quarters  the  elvers  begin  to  feed  and 
to  grow,  and  are  now  known  as  "yellow  eels." 
Their  food  consists  at  first  of  worms,  larvae, 
and  small  fishes,  but  as  they  grow  they  become 
very  voracious,  and  will  attack  water  voles 
and  water-fowl,  and  even  larger  fishes,  among 
which  they  do  serious  damage.  There  is  even 
a  case  on  record  of  an  eel,  5  feet  long,  which 
attacked  a  swan!  The  owner  saw  the  swan 
struggling  violently,  with  its  head  under 
water.  He  went  to  its  assistance  and  found 
that  its  head  had  been  seized  by  a  large  eel, 
which  held  on  so  obstinately  that  it  allowed 
itself  to  be  caught  and  landed. 

About  the  third  summer  of  an  eel's  life  in 
fresh  water  its  scales  begin  to  grow.  It  is  an 
interesting  fact  that  naturalists  can  tell  the 
age  of  an  eel,  or  at  least  the  length  of  time  it 
has  spent  in  fresh  water,  by  examining  its 
scales  under  the  microscope.  Each  scale  is 
arranged  in  little  zones  or  rings  studded  with 
tiny,  limy  knobs,  separated  by  narrow  rings 
of  smooth  material.  "This  structure  is  due 


1 66  THE  HAUNTS  OF  LIFE 

to  the  fact  that  the  eel  feeds  and  grows  actively 
in  the  summer  months  only,  and  the  zones  are 
annual  rings  formed  during  the  summer, 
whilst  the  narrow  interspaces  represent  the 
growth  of  the  scale  during  the  colder  months." 

After  a  varying  time,  usually  four  to  six 
years  in  the  males,  and  seven  to  eight  in  the 
females,  the  yellow  eels  begin  to  change  to 
"silver  eels."  Their  eyes  grow  larger,  their 
pectoral  fins  longer,  and  they  become  silvery- 
white  on  the  under-side  of  the  body.  This  is 
their  breeding-dress,  and  they  are  putting  it 
on  in  preparation  for  the  long  journey  back 
to  the  sea. 

They  have  practically  ceased  to  feed  by  this 
time,  and  they  make  the  journey  down  the 
rivers  in  vast  numbers,  just  as  they  came  up. 
But  this  time  they  travel  by  night,  and  then 
only  when  it  is  quite  dark;  bright  moonlight, 
or  a  flash  of  artificial  light,  will  send  them  into 
hiding  at  once.  During  this  journey  they  are 
caught  in  great  numbers  in  traps  and  nets  of  all 
kinds,  for  at  this  stage  they  are  much  valued 
as  food,  though  in  Scotland,  for  instance, 
there  is  a  good  deal  of  prejudice  against  them. 

Both  the  last  chapter  and  the  first  in  the 
story  of  the  eel's  life  remain  obscure.  No  one 


THE  FRESH  WATERS  167 

has  yet  identified  the  eggs  with  certainty,  nor 
the  very  youngest  forms  of  the  fish.  Minute 
fry  are  now  known,  however,  which  grow  into 
3-inch  long  transparent  larvae,  which  feed 
near  the  surface  of  the  Atlantic  by  night,  and 
sink  deeper  through  the  day.  Some  of  these 
"  Leptocephalids,"  which  had  long  been  a 
puzzle  to  naturalists,  were  kept  in  an  aqua- 
rium, and  their  gradual  transformation  to  the 
elver  stage  was  observed.  Then  many  of 
them  were  taken  at  different  times  from  the 
sea,  and  it  was  learnt  that  towards  the  end  of 
summer  they  begin  to  undergo  a  change  into 
the  "glass-eel,"  or  "transparent  elver"  stage. 
At  the  same  time,  apparently,  they  begin  their 
migration  towards  the  shore.  The  process  of 
changing  goes  on  for  many  months,  and,  dur- 
ing that  time,  they  do  not  feed  at  all,  but  live 
on  their  own  substance.  The  elver  is  not  only 
quite  different  in  shape  from  the  earlier  form, 
being  now  a  small  eel,  but  it  is  fully  half  an 
inch  shorter. 

As  to  the  last  chapter,  it  is  supposed  that 
the  silver  eels  from  the  British  Isles  go  out 
to  the  deep  waters  of  the  Atlantic  and  there 
deposit  their  eggs,  which  rise  to  the  surface 
and  float  till  they  hatch.  The  eels  themselves, 


1 68  THE  HAUNTS  OF  LIFE 

like  many  other  animals,  probably  die  after 
the  eggs  are  safely  deposited,  for  none  of 
them  ever  reappear  at  the  coasts  or  in  the 
rivers  after  spawning. 

There  are  only  a  few  species  of  eel  which 
enter  fresh  water;  the  great  majority  of  the 
family  spend  their  whole  lives  in  the  sea, 
many  of  them  in  deep  water.  Moreover, 
some  individuals,  even  of  the  common  eel,  do 
not  enter  the  rivers,  but  probably  remain 
about  the  estuaries  till  it  is  time  to  return  to 
deeper  water. 

On  the  other  hand,  some  yellow  eels  do  not 
return  to  the  sea.  They  may  have  settled 
down  in  ponds  which  they  found  it  easy  to 
reach  when  they  were  little  elvers,  but  dif- 
ficult to  escape  from  later,  or  they  may  lack 
the  impulse  to  migrate.  Such  eels  may  live 
a  long  time  and  grow  to  a  great  size,  but  they 
never  produce  eggs. 

All  these  facts  justify  the  conclusion  that 
the  common  eel  is  descended  from  ancestors 
which  were  entirely  sea-fish,  and  that  it  has 
taken  to  a  fresh-water  life.  Whether  it  will 
go  farther  in  the  same  direction,  we  have  no 
means  of  knowing. 

We  have  followed  this  story  at  some  length, 


THE  FRESH  WATERS  169 

partly  because  it  is  so  wonderful  in  itself,  but 
partly  also  so  that  we  may  get  some  under- 
standing of  the  methods  by  which  naturalists 
interpret  for  us  some  of  Nature's  stories,  and 
of  the  long  and  patient  labour  that  is  required 
to  determine  the  facts. 

THE  STORY  OF  THE  SALMON 

Let  us  now  think  for  a  little  of  another  life- 
story  that  is  in  some  ways  just  the  opposite  of 
the  eels — that  of  the  King  of  Fishes,  the 
Salmon,  which  is  so  valuable  as  a  food,  and 
which  is  also  prized,  because  its  courage  and 
strength  make  the  catching  of  it  good  sport. 

Salmon  ascend  most  of  our  larger  rivers — if 
they  are  clean  enough — every  year,  but  not  in 
swarms  as  the  eels  do;  they  continue  to  go  up 
throughout  the  spring  and  summer.  Nor  are 
they  all  of  one  age  and  size  like  the  eels.  But 
all  of  them  are  impelled  by  the  desire  to  reach 
a  suitable  breeding-place.  They  are  in  the 
finest  possible  condition  when  they  enter  fresh 
water — fat,  with  firm,  red  flesh  and  silvery 
skin — for  they  have  been  feeding  hard  and 
laying  up  stores  of  food-material  and  strength, 
which  have  to  last  them  till  after  the  spawn- 


170  THE  HAUNTS  OF  LIFE 

ing-time,  often  many  weeks  ahead.  While  in 
fresh  water  they  feed  very  little,  if  at  all. 

They  need  all  their  muscular  energy,  too, 
for  there  are  many  obstacles  to  be  overcome 
on  their  way  up  the  rivers,  and  the  salmon  gets 
his  name  from  his  power  of  leaping.  They  are 
said  to  be  able  to  leap  up  falls  as  high  as  10 
feet,  and  their  courage  and  persistence  in  re- 
turning again  and  again  to  the  charge  after 
failure  has  thus  been  described:  "The  lithe 
body,  less  silvery  than  usual,  shot  out  of  the 
water;  then  followed  a  plucky  rush  amid  the 
bubbles ;  then  in  seven  cases  out  of  ten  the  fish 
was  swept  back  before  it  had  cleared  the  sec- 
ond rung  of  the  ladder.  It  was  as  exciting  as 
a  race-course.  The  favourite  cleared  one  bar- 
rier after  another,  lost  energy  at  the  last,  and 
was  swept  back  like  a  log,  while  another,  with 
less  dash  about  him,  cleared  every  one,  and 
shot  ahead  in  the  swift,  smooth,  sullen  water 
above  the  fall.  There  was  pathos  in  the  pas- 
sivity with  which  the  unsuccessful  swimmer 
let  himself  be  swirled  back  to  the  eddies  at  the 
foot  of  the  ladder.  Like  a  spent  horse,  he  could 
no  more,  but  one  knew  that  he  was  setting 
his  teeth,  so  to  speak,  for  the  next  rush." 

Arrived  at  the  spawning-place — a  gravel  bed 


THE  FRESH  WATERS  171 

in  a  shallow  part  of  the  river — the  female  sal- 
mon lashes  out  a  trough  with  her  tail,  and  in  it 
deposits  her  eggs,  moving  gradually  up  stream 
as  she  does  so.  The  attendant  male  meantime 
keeps  all  intruders  fiercely  at  bay.  After 
spawning  the  salmon  are  much  exhausted,  and 
they  linger  for  a  time  in  the  deep  pools  to  re- 
cover, but  they  do  not  begin  to  feed  actively 
even  then,  and  many  of  them  die  of  weakness 
or  disease  on  their  way  back  to  the  sea. 

The  young  fry  emerge  in  early  spring  and, 
for  the  first  few  weeks,  remain  quietly  hidden 
among  the  gravel,  depending  for  nourishment 
on  the  stores  laid  up  for  them  in  the  egg,  and 
now  attached  to  their  bodies  as  a  yolk-sac. 
When  the  yolk  is  exhausted,  and  they  are 
about  an  inch  long,  they  become  more  active, 
and  seek  for  their  own  food.  During  all  this 
time  both  eggs  and  fry  are  preyed  upon  by 
many  enemies,  of  which  the  eels,  pike,  and 
fish-eating  birds  probably  do  most  damage. 
But  the  young  ones  that  are  left,  now  known 
as  "parr,"  continue  to  feed  and  grow  for  a 
couple  of  years,  and  then,  assuming  more  sil- 
very hues,  descend  as  "  smolts "  to  the  sea.  At 
this  stage  they  are  about  6  or  7  inches  long, 
but  the  abundance  of  food  in  the  sea,  where 


172  THE  HAUNTS  OF  LIFE 

they  live  chiefly  on  herring,  mackerel,  etc., 
makes  them  grow  very  rapidly,  and  those  that 
ascend  the  rivers  as  "grilse"  the  following 
year  are  often  more  than  double  that  length. 
Many  of  them,  however,  spend  two  or  three  or 
more  years  in  the  sea  before  they  return,  and 
these  grow  to  a  great  size.  Some  do  not  return 
at  all,  but  remain  about  the  estuaries.  It  is  un- 
likely that  those  that  do  this  ever  breed ;  spawn- 
ing is  only  known  to  take  place  in  fresh  water. 

THE  STORY  OF  THE  LAMPREY 

One  of  the  most  interesting  animals  that 
live  in  fresh-running  water  is  the  lamprey. 
It  is  not  very  easy  to  see,  for  most  of  its  life 
is  spent  concealed  in  the  sand.  But  at  the 
breeding  season  it  comes  out  of  its  hiding- 
place,  and  begins  to  make  preparations  for 
the  advent  of  the  next  generation. 

Let  us  look  for  a  moment  at  the  lamprey 
itself.  The  common  brook-lamprey  is  eel-like 
in  appearance,  and,  when  full  grown,  is  about 
7  inches  long.  Its  skeleton  is  gristly  instead 
of  bony,  like  that  of  the  true  fishes.  It  has 
two  fins  on  the  middle  line  of  the  back  and  a 
tail-fin,  but  no  paired  fins.  It  has  no  jaws, 


THE  FRESH  WATERS  173 

but  it  has  a  round  sucker-mouth,  and  a  very 
muscular  tongue,  covered  with  horny  teeth. 
With  its  sucker-mouth  it  fastens  itself  to  the 
body  of  a  fish,  and,  protruding  its  rough 
tongue,  proceeds  to  rasp  the  flesh  off  its  un- 
fortunate victim.  Fishes  have  sometimes  been 
seen  to  turn  over  on  their  sides,  so  that  the 
troublesome  "boarder"  is  out  of  water,  and 
is  forced  to  let  go  its  hold. 

Along  each  side  of  the  body  of  the  lamprey, 
near  the  head,  there  are  seven  conspicuous 
holes.  These  are  the  gill-slits,  and  the  gills 
to  which  they  lead  are  continually  washed  by 
water.  In  most  fishes,  water  enters  by  the 
mouth  and  flows  out  at  the  gill-slits,  carrying 
away  the  used  air  from  the  blood.  But  the 
lamprey  uses  its  mouth  to  fasten  itself  to  its 
prey,  and,  in  its  case,  water  flows  in  at  the 
gill-slits  and  out  again. 

The  eyes  are  large,  and  there  is  a  single 
nostril,  which  lies  right  in  the  middle  line  of 
the  head  so  that,  whichever  side  of  the  body 
we  look  at,  we  see  an  eye  and  eight  holes. 
This  is  why  lampreys  are  popularly  called 
"nine-eyes"  or  "niners." 

As  spawning-time  approaches,  the  lampreys, 
both  male  and  female,  set  about  preparing  a 


174  THE  HAUNTS  OF  LIFE 

safe  place  for  the  eggs.  They  choose  out  a 
spot  with  a  sandy  bottom  and,  attaching  them- 
selves by  their  sucker-mouths  to  any  stones 
upon  it,  they  pull  these  to  the  lower  part  of 
their  chosen  site,  thus  making  a  little  dam 
which  will  keep  the  eggs  from  being  washed 
away.  Then  they  fasten  themselves  to  a  stone 
at  the  upper  edge  of  their  pool,  and  lash  up 
the  sand  with  their  tails,  while  some  of  the 
eggs  and  sperms  are  discharged  into  the  water. 
The  eggs  sink  to  the  bottom,  and  the  sand 
settles  over  them.  More  stones  are  added  to 
the  wall  of  the  dam,  and  the  laying  process  is 
repeated  at  intervals.  Sometimes  a  number 
of  lampreys  combine  to  make  a  nest,  and  they 
may  be  seen  hanging  in  a  cluster  from  a  stone. 
When  spawning  is  over,  the  lampreys  are  so 
exhausted  that  they  never  recover;  they  float 
away  downstream  and  soon  die. 

The  eggs  hatch  out  in  about  three  weeks. 
The  young  ones  are  quite  different  from  their 
parents,  and  got  their  common  name  of 
"  Prides "  long  before  it  was  known  what  they 
really  were.  They  are  yellowish,  worm-like 
creatures,  with  no  visible  eyes,  and  a  horseshoe 
mouth.  They  make  a  kind  of  tunnel  open  at 
both  ends  in  the  sand,  and  spend  all  their  time 


THE  FRESH  WATERS  175 

there,  wriggling  farther  in  when  disturbed. 
They  take  four  years  to  reach  their  full  size, 
and  then,  within  a  few  weeks,  they  undergo 
the  change  to  the  adult  form. 

The  River  Lamprey,  which  is  still  abundant 
in  the  Severn  and  some  other  English  rivers, 
grows  larger,  and  usually  spends  a  part  of  its 
life  in  the  sea.  It  used  to  be  considered  a  table 
delicacy,  and  it  was  from  the  effects  of  too 
hearty  a  meal  of  these  lampreys  that  Henry  II. 
is  said  to  have  died.  They  are  still  caught  in 
considerable  numbers,  but  are  chiefly  used  for 
bait.  There  is  a  still  larger  Sea  Lamprey, 
that  spawns  in  rivers. 

FROM  WATER  TO  LAND 

We  shall  find  an  instance  of  animals  that 
seem  to  be  on  their  way  from  fresh  water  to 
terrestrial  life  in  a  very  familiar  group — the 
frogs  and  toads,  with  their  more  distant  cou- 
sins, the  newts  and  salamanders. 

We  need  not  go  over  the  life-history  of  the 
frogs  and  toads,  because  any  of  us  can  watch  it 
for  ourselves,  and  it  is  very  much  better  to  see 
things  than  to  read  about  them  if  it  is  possible. 
We  have  only  to  listen  for  the  croaking  of  the 


176  THE  HAUNTS  OF  LIFE 

frogs  in  March  or  April,  then  look  for  the 
clumps  of  jelly-like  eggs,  take  them  home  and 
keep  them  in  a  properly  shaded  vessel,  and  we 
can  follow  the  whole  fascinating  story.  But  we 
must  be  careful  to  keep  water-plants  growing 
in  our  aquarium,  that  the  water  may  be  aerated, 
to  supply  food,  but  to  remove  all  decaying 
matter,  and  to  provide  a  foothold  for  the  little 
creatures  when  they  are  about  to  make  their 
great  change  from  the  tadpole  to  the  frog  stage. 

All  the  members  of  the  group  have  in  their 
full-grown  state  the  great  characteristic  of 
adult  terrestrial  animals — they  breathe,  by 
means  of  lungs,  the  oxygen  in  the  air.  But  the 
young  of  almost  all  of  them  have  gills 
and  breathe  the  oxygen  dissolved  in  water. 
The  time  the  tadpole  breathes  by  gills  may 
be  longer  in  one  family  than  another,  it  may 
even  vary  in  the  same  family,  according  to 
surroundings  and  weather,  but,  long  or  short, 
it  is  very  rarely  omitted. 

Another  fact  that  shows  the  direction  in 
which  they  are  tending  is  that  even  the  adults 
are  not  all  equally  terrestrial  in  habit.  Both 
frogs  and  toads  spend  some  time  in  the  water 
in  spring,  and  leave  it  when  their  eggs  are 
safely  deposited.  But  as  winter  approaches, 


THE  FRESH  WATERS  177 

the  toad  buries  itself  among  withered  leaves, 
or  in  some  dry  spot,  while  the  frog  returns 
to  the  pond  or  ditch  and  hides  itself  in  a  hole, 
perhaps  in  a  drain-pipe,  it  may  even  be  in 
the  damp  mud. 

But  the  frog  has  long  ago  lost  its  gills,  and 
its  lungs  are  closed  in  winter  by  the  shutting  ' 
of  the  nostrils.  How  then  does  it  breathe,  for 
breathe  it  must,  even  though  the  fires  of  life 
are  very  low?  The  skin  is  exceedingly  thin 
and  delicate,  and  there  is  a  network  of  very 
fine  blood-vessels  all  over  it,  and  the  exchange 
of  gases — used  carbonic  acid  gas  for  fresh 
oxygen,  which  is  the  essential  part  of  breath- 
ing— takes  place  directly  from  these  blood- 
vessels through  the  skin. 

WATER  INSECTS 

One  more  group  we  must  think  of  for  a 
little — the  aquatic  insects. 

All  fully  developed  insects  breathe  air 
through  little  openings  on  the  surface  lead- 
ing into  fine  tubes,  called  tracheae,  which 
carry  the  air  to  all  parts  of  the  body.  Even 
insects  which  spend  their  whole  lives  on  and 
in  the  water  breathe  in  this  way.  They  may 


178  THE  HAUNTS  OF  LIFE 

be  able  to  remain  under  water  for  consider- 
able periods,  because  they  have  various  ways 
of  carrying  reserves  of  air,  as  bubbles  en- 
tangled among  the  body-hairs,  for  instance, 
while  others  are  able  to  use  the  oxygen  mixed 
with  the  water. 

In  addition  to  these,  many  insects,  such  as 
the  gnats,  may-flies,  caddis-flies,  and  the  beau- 
tiful big  dragon-flies,  lay  their  eggs  in  the 
water,  and  the  great  changes  from  egg  to 
larva,  from  larva  to  the  "  resting-stage,"  which 
is  a  preparation  for  the  emergence  of  the  per- 
fect insect,  are  gone  through  in  the  water. 
Yet  this  is  not  a  case  in  which  an  aquatic  race 
is  on  the  way  to  terrestrial  life;  they  are  not 
water-breathers,  they  are  air-breathers,  which 
have  adopted  the  habit  of  laying  their  eggs 
in  the  water  for  the  greater  safety  of  the 
young.  Many  of  the  larvae  have  become  so 
well  adapted  to  aquatic  life  that  they  are  able 
to  breathe  dissolved  air  by  gills,  but  these 
"tracheal  gills,"  as  they  are  called,  are  de- 
veloped from  the  air-tubes  which  are  present, 
even  though  the  openings  to  them  are  closed. 
And  many  of  the  larvae  breathe  surface  air 
from  the  first.  The  gnat  larvae,  which  we  may 
find  in  any  ditch,  have  a  breathing-tube  pro- 


THE  FRESH  WATERS  179 

jecting  from  the  last  ring  of  their  bodies,  and 
may  be  seen  hanging  head  downwards  from 
the  surface  so  that  air  may  enter.  There  are 
other  aquatic  larvae  which  never  even  get  wet. 
This  is  difficult  to  understand,  because  it  re- 
quires a  knowledge  of  physical  properties,  but 
it  is  a  fact,  and  it  is  illustrated  in  a  very  varied 
way  among  animals  that  have  gone  back  from 
the  dry  land  to  the  water.  Some  water-beetles 
can  hardly  become  wet  at  all ;  some  keep  the 
greater  part  of  the  body  dry,  but  not  it  all ; 
some  become  quite  wet.  The  little  whirligig 
beetle  (Gyrinus)  and  the  Water  Boatmen 
(Notonecta)  become  very  slightly  wetted. 
The  water-spider  remains  dry  over  a  consid- 
erable part  of  the  hairy  body. 

The  time  spent  in  the  water  is  often  very 
long  compared  with  the  aerial  life.  Some  of 
the  caddis-flies  are  said  to  spend  three  years 
in  the  water,  and  then  only  to  live  a  few  days. 
And  some  aerial  lives  are  shorter  still.  Some 
of  the  May-flies  or  Ephemeridae,  as  they  are 
called,  from  the  shortness  of  their  lives,  live 
only  a  few  hours  as  winged  insects  in  the  air. 
But  their  larval  life  in  the  water  lasts  for  two 
or  three  years,  during  which  they  feed,  grow, 
and  cast  their  husk  many  times.  At  length 


i8o  THE  HAUNTS  OF  LIFE 

there  is  the  making  of  the  wings  and  the  event- 
ful emergence  from  the  water.  They  cannot 
fly  much  at  first,  for  they  are  encumbered  by 
a  thin  veil  too  truly  suggestive  of  a  shroud. 
They  rest  rather  wearily  on  the  branches  of 
the  willows,  and  on  our  clothes,  as  we  watch 


FIG.  17. — GARDEN  SPIDER  (EPEIRA 
DIADEMA). 

them.  We  see  them  writhe  and  jerk,  till  at 
length  their  last  encumbrance,  their  "  ghost," 
as  some  entomologists  have  called  it,  is  thrown 
off.  Then  the  short  aerial  life  begins;  they 
swing  to  and  fro  as  in  a  dance ;  they  dimple  the 


THE  FRESH  WATERS  181 

smooth  surface  of  the  water  with  a  touch  into 
smiling;  we  see  them  chasing,  embracing, 
separating.  There  is  great  beauty  in  their  film- 
like  wings,  in  their  large,  lustrous  eyes,  in  the 
graceful  sweep  of  the  long  tail-filaments. 

"They  never  pause  to  eat;  they  could  not 
if  they  would.  Hunger  is  past,  love  is  just 
begun,  and  in  the  near  future  is  death.  The 
evening  shadows  grow  longer — the  shadow  of 
death  is  over  the  Ephemerides.  The  trout 
jump  at  them,  a  few  raindrops  thin  the 
throng,  the  stream  bears  others  away.  The 
mothers  lay  their  eggs  in  the  water,  and,  after 
doing  so,  many  seem  utterly  spent,  and  die 
forthwith.  The  eggs,  however,  are  in  the 
water,  and  the  race  continues." 


THE  STORY  OF  THE  FRESH-WATER 
SPIDER 

Before  we  leave  the  fresh  waters,  let  us  look 
at  the  water-spider  (Argyroneta  natans),  one 
of  the  conquerors.  It  strikes  the  note  of  ad- 
venture which  is  so  characteristic  of  animals. 
For  while  it  is  a  land  animal  by  nature  and 
origin,  and  breathes  dry  air,  it  has  learned  to 
live  underneath  the  water.  It  is  the  female 


FIG.  18.— THE  FEMALE  FRESH-WATER  SPIDER  (ARGYRONETA  NATANS). 

It  has  made  a  Diving-bell-like  Web,  buoyed  into  a  Dome  with  Air. 

Note  Air  entangled  on  Spider's  Body.    Note  special  lines  to  Surface. 


THE  FRESH  WATERS  183 

water-spider  who  is  particularly  admirable,  so 
we  shall  henceforth  say  "she."  She  spins  a  / 
flattish  web  beneath  the  water,  and  moors  it 
with  silk  threads  like  tent-ropes  to  stones  and 
weeds.  A  special  line  runs  up  to  the  surface 
and  is  fixed  to  a  floating  plant.  Up  and  down 
this  rope  the  spinner  goes  many  times;  at  the 
surface  she  gets  air  entangled  in  the  hairs  of 
her  body;  she  climbs  down,  looking  like  a 
drop  of  quicksilver  in  the  water — the  air 
glistens  so;  she  brushes  her  hair  with  her  legs, 
and  the  air-bubbles  are  caught  underneath  the 
web,  which  thus  becomes  buoyed  up  like  a 
dome  or  like  an  anticipation  of  a  diving-bell. 
After  many  journeys  up  and  down  the  web  is 
full  of  dry  air,  and  there  the  spider  deposits 
her  eggs  and  rears  her  young.  Sometimes 
when  she  is  in  a  hurry  she  gets  into  the  empty 
shell  of  a  water-snail  and  manages,  we  do  not 
quite  know  how,  to  fill  it  with  air  brought 
down  from  the  surface.  There  are  many  in- 
teresting facts  about  the  water-spider,  for  in- 
stance, how  she  arranges  tags  of  silk  among 
her  hair,  which  probably  help  in  entangling 
the  air-bubbles.  For  reasons,  rather  difficult 
to  explain,  she  never  gets  wet.  But  the  big 
interest  is  just  that  this  spider  found  an  empty 


1 84  THE  HAUNTS  OF  LIFE 

corner — an  empty  niche  of  opportunity — full 
of  difficulties,  to  be  sure,  but  offering  new 
opportunities  of  food  and  safety.  How  splen- 
didly well  has  she  overcome  the  difficulties 
and  used  the  opportunities. 


CHAPTER  V 

THE  CONQUEST  OF  THE  DRY 
LAND 

Tell-tale  Evidences  of  Marine  Ancestry  —  Origin  of  Land 
Plants  —  The  Three  Great  Invasions  of  the  Dry  Land  — 
New  Ways  of  Breathing  —  Changes  in  Movements  —  New 
Ways  of  Looking  after  the  Young—  New  Kinds  of  Pro- 
tection —  Betwixt-and-Between  Animals  —  Haunts  within 
Haunts  —  Beneath  the  Ground  —  Cave  Animals—  Arboreal 
Life. 


and  over  again  in  the  history  of 
animal  life  some  adventurous  members 
of  aquatic  races  have  become  colonists  of  the 
dry  land.  Perhaps  we  should  not  be  quite 
wrong  if  we  said,  a  little  fancifully,  that  one 
of  the  great  unspoken  wishes  of  animals  was 
to  get  out  of  the  water.  In  any  case,  it  is 
almost  certain  that  the  great  majority  of  the 
different  classes  of  land  animals  had  their  an- 
cestry in  the  sea,  some  of  them  making  the 
transition  —  which  might  require  millions  of 
years  —  through  fresh  waters. 

We  must  be  careful  here  to  see  the  facts 
clearly.     Land  mammals  had  their  origin  in 
185 


1 86  THE  HAUNTS  OF  LIFE 

land  reptiles,  and  birds  had  their  origin  in 
land  reptiles — where  then  is  the  marine  an- 
cestry? But  the  reptiles  sprang  from  an  an- 
cient amphibian  stock,  whose  very  name,  am- 
phibian, suggests  that  they  lived  partly  in 
water  and  partly  on  land.  And  these  am- 
phibians sprang  from  fishes,  and  the  original 
fishes  were  in  the  sea.  So  that  when  we  say  that 
the  ancestors  of  land  animals  were  marine,  we 
usually  mean  their  distant  ancestors,  belonging 
perhaps  to  a  much  simpler  class.  On  the  other 
hand,  when  we  look  at  the  terrestrial  crusta- 
ceans, called  wood-lice  or  slaters,  which  we  see 
running  about  if  we  turn  over  loose  stones  or 
strip  off  loose  bark,  we  may  safely  say  these  are 
the  direct  descendants  of  sea-slaters,  such  as 
we  find  to-day  among  the  rocks  on  the  shore. 


TELL-TALE  EVIDENCES  OF  MARINE 
ANCESTRY 

It  may  be  asked,  however,  why  land  ani- 
mals may  not  have  begun  their  existence  on 
land,  instead  of  being  derived  from  distant 
ancestors  in  the  sea.  This  is  a  good  question, 
which  requires  a  longer  answer  than  is  pos- 
sible here.  But  part  of  the  answer  is  this. 


THE  CONQUEST  OF  THE  DRY  LAND      187 

Land  animals  carry  about  in  their  bodies  the 
tell-tale  evidences  of  a  marine,  or  at  least  of 
an  aquatic,  ancestry.  Thus  all  the  embryos  of 
reptiles,  birds,  and  mammals  have  gill-clefts 
on  the  sides  of  their  neck,  opening  into  the 
pharynx  (the  beginning  of  the  food-canal,  just 
behind  the  mouth),  and  in  two  or  three  cases, 
in  reptile  and  bird,  tuft-like  traces  of  the  gills 
themselves  have  been  recently  discovered. 
These  gill-clefts  are  of  no  use  for  breathing 
in  reptiles,  birds,  and  mammals;  indeed,  we 
cannot  say  that  they  are  of  any  use  at  all,  ex- 
cept the  first  one,  which  becomes  a  tube  (the 
Eustachian  tube,  named  after  an  old  anato- 
mist) leading  from  the  ear-passage  to  the  back 
of  the  mouth.  But  these  gill-clefts  are  always 
present,  and  they  must  be  regarded  as  historic 
relics.  As  Darwin  said,  they  are  like  un- 
sounded letters  in  words,  which  tell  us  part  of 
the  history  of  the  word.  Thus  the  unsounded 
o  in  leopard  tell  us  that  this  animal  used  to 
be  regarded  as  a  cross  between  a  lion  and  a 
tiger  (or  pard).  So  there  are  vestiges  in  land 
animals  which  betray  their  aquatic  ancestry. 
In  the  ear-passage  of  a  mammal  there  is  a 
drum  or  tympanum  stretched  across  just  a  lit- 
tle way  below  the  surface.  On  this  drum  the 


1 88  THE  HAUNTS  OF  LIFE 

waves  of  sound  strike ;  this  is  the  door  at  which 
they  knock.  But  the  vibrations  have  to  be 
conveyed  to  the  real  ear — the  delicate  organ  of 
hearing — which  is  safely  lodged  in  very  dense 
bone  (periotic)  deeper  down  in  the  skull.  Now, 
running  from  the  drum  of  the  ear  to  the  inner 
ear,  there  is,  in  mammals,  a  chain  of  three 
little  bones  called  the  Hammer,  the  Anvil, 
and  the  Stirrup  (Malleus,  Incus,  and  Stapes). 
What  do  these  turn  out  to  be?  Their  develop- 
ment shows  that  they  are  just  transformed 
pieces  of  bone  which,  in  fishes,  form  part  of 
the  commonplace  framework  of  the  jaws. 
This  is  another  tell-tale  evidence  of  the  very 
distant  aquatic  ancestry  of  mammals. 

Another  very  remarkable  fact  has  to  do 
with  the  blood.  Many  of  the  lower  animals, 
such  as  sponges  and  jelly-fishes,  sea-anemones 
and  corals,  and  the  simpler  worms,  have  no 
blood;  but  every  one  knows  that  this  is  very 
unusual.  From  ringed  worms  to  man,  almost 
all  animals  have  blood,  though,  in  many  cases, 
like  lobster  and  snail,  it  is  not  very  noticeable, 
being  practically  colourless.  This  blood  is  a 
very  complex,  chemical  mixture;  its  watery 
basis  contains  solutions  of  salts,  sugar,  pro- 
teins, and  nitrogenous  waste-products.  Every 


THE  CONQUEST  OF  THE  DRY  LAND   189 

boy  who  has  put  his  bleeding  finger  to  his 
mouth  knows  that  the  blood  has  a  salt  taste. 
And  it  is  very  remarkable  that  the  salts  in  the 
blood  are  in  the  main  the  salts  of  the  sea,  and 
that  they  occur  in  very  much  the  same  pro- 
portions as  in  the  sea.  The  correspondence 
becomes  closer,  when  we  take  into  account  the 
change  in  the  composition  of  the  sea  since 
blood  was  first  established  millions  and  mil- 
lions of  years  ago.  This  tells  a  tale. 

We  cannot  turn  back  the  hands  of  the 
world-clock,  and  get  it  to  strike  over  again 
the  hours  that  are  past,  but  there  is  the  rock- 
record  to  help  us  to  get  away  from  conjec- 
ture. And,  as  we  have  just  seen,  some  help 
is  to  be  got  from  the  individual  development 
which  is,  in  some  measure,  in  the  making 
of  organs  and  the  building  up  of  the  body, 
a  recapitulation — much  condensed  and  tele- 
scoped— of  the  history  of  the  race. 

We  should  also  remember  that  some  of  the 
changes  we  suppose  to  have  occurred  millions 
of  years  ago  have  their  counterparts  in 
changes  that  are  taking  place  to-day.  Evolu- 
tion is  not  something  done  with;  it  is  going 
on.  Thus  the  Robber-Crab  is  a  shore-animal 
in  process  of  becoming  terrestrial. 


190  THE  HAUNTS  OF  LIFE 

There  is  another  reason  why  it  is  not  easy  to 
think  of  land  animals  beginning  on  the  dry 
land;  the  conditions  of  life  are  too  difficult 
for  beginners  or  apprentices.  This  will  become 
clearer  later  on,  but  it  may  be  noticed  that 
breathing  and  moving,  and  the  disposal  of  the 
eggs  or  young,  are  much  more  difficult  on  land 
than  in  the  water.  As  it  is  much  more  diffi- 
cult to  escape  from  enemies  when  movement 
is  all  in  one  plane,  we  cannot  wonder  that 
many  land  animals  have  become  burrowers, 
and  other  climbers,  and  others  fliers,  that 
others  have  become  camouflaged,  and  that 
others  have  taken  to  coming  out  at  night  only. 
But  we  shall  return  to  this  subject  later  on. 

ORIGIN  OF  LAND  PLANTS 

When  we  consider  the  sand-dunes,  the  rocky 
islands,  the  deserts,  the  mountain-tops,  and  so 
on — we  feel  at  once  that  there  are  many  parts 
of  the  dry  land  which  cannot  be  called  very 
hospitable  to  living  creatures.  The  dry  land 
is  a  haunt  very  much  more  difficult  than  the 
sea  or  the  lake.  The  fact  is  that  no  greaf 
colonisation  by  animals  was  possible  until 
plants  had  prepared  the  way.  They  provided 


THE  CONQUEST  OF  THE  DRY  LAND      191 

food,  shelter,  and  moisture.  They  were  the 
pioneers  for  animals,  and  the  simpler  plants 
likewise  made  higher  plants  possible. 

According  to  the  rock-record,  long  ages 
passed  before  land  plants  began.  For  while 
there  are  fossil  remains  of  seaweeds  in  very 
ancient  rocks,  there  is  no  definite  evidence  of 
land  plants  till  millions  and  millions  of  years 
had  passed.  It  was  not  till  ages  after  that 
(early  Tertiary)  that  grass  began  to  cover  the 
earth  like  a  garment — an  event  with  far- 
reaching  consequences. 

As  to  the  origin  of  land  plants,  there  are  two 
theories.  It  is  possible  that  very  simple  plants 
migrated  from  the  sea  to  the  fresh  waters,  and 
thence  to  swampy  ground;  and  that  a  fresh 
start  was  made  there  which  gradually  led  to  a 
land  vegetation.  But  one  of  the  most  thought- 
ful botanists  of  to-day,  Prof.  A.  H.  Church,  has 
recently  argued  that  the  highly  developed  shore 
vegetation  of  seaweeds  may  have  given  origin 
to  the  dry-land  plants  by  gradual  transforma- 
tion. There  is  no  doubt  that  the  seaweeds  have 
attained  great  complexity  of  structure,  and  it 
may  be  that  instead  of  representing  a  gorgeous 
blind  alley,  they  point  the  way  to  higher  plants. 
If  the  coast  was  slowly  raised,  as  it  often  was, 


192  THE  HAUNTS  OF  LIFE 

the  great  seaweeds  might  be  gradually  trans- 
formed into  terrestrial  plants.    Who  knows? 


THE  THREE  GREAT  INVASIONS  OF  THE 
DRY  LAND 

In  the  conquest  of  the  dry  land  we  can  dis- 
tinguish three  great  invasions  or  colonisations. 
The  first  was  the  Worm-Invasion,  led  by  sim- 
ple worms  such  as  the  land-planarians,  which 
had  begun  the  profitable  habit  of  moving  with 
one  end  of  the  body  always  in  front.  In  ma- 
rine animals  of  comparatively  low  degree, 
such  as  jelly-fishes  and  swimming-bells,  sea- 
anemones  and  corals,  the  symmetry  of  the 
body  is  more  or  less  radial,  that  is  to  say,  there 
is  no  right  or  left,  no  head-  or  tail-end.  The 
body  can  be  cut  into  two  almost  identical 
halves  along  many  different  planes.  Radial 
symmetry  may  be  illustrated  by  an  orange  and 
by  the  circular  plate  it  rests  on.  It  is  well 
suited  for  easy-going  life,  for  drifting  in  the 
sea,  or  for  waiting  for  food  to  drop  into  the 
mouth.  But  certain  worms  acquired  bilateral 
symmetry,  moving  with  one  end  of  the  body 
always  in  front.  This  was  better  suited  for 
quick  and  definite  movements,  such  as  are 


THE  CONQUEST  OF  THE  DRY  LAND     193 

needed  in  the  pursuit  of  prey  or  the  avoidance 
of  enemies.  And  as  the  acquisition  of  bilateral 
symmetry  was  associated  with  the  acquisition 
of  head-brains,  we  may  say  that  it  was  the  be- 
ginning of  our  knowing  our  right  hand  from 
our  left.  In  any  case,  radial  symmetry  is  out  of 
the  question  on  dry  land,  and  the  first  colonisa- 
tion was  attempted  by  simple  bilateral  worms. 

The  most  important  members  of  the  "  worm- 
invasion"  were  the  earthworms,  which  prob- 
ably evolved  from  a  fresh-water  stock.  This 
is  suggested  by  earthworms  like  Alma  and 
Dero,  which  have  gills,  and  there  are  many 
not  very  distant  relatives  of  earthworms  now 
at  home  in  fresh  water,  such  as  Nais  and 
Tubifex,  common  in  streams.  The  impor- 
tance of  earthworms  in  the  conquest  of  the 
dry  land  is  well  known,  for  they  have  made 
the  fertile  soil  of  the  globe.  Their  successful 
possession  of  the  subterranean  world  at  an 
early  date  implies  the  previous  establishment 
of  some  terrestrial  vegetation,  for  earthworms 
depend  for  food  on  the  plant  remains  in  the 
earth,  which  they  swallow,  and  on  such  frag- 
ments as  they  are  able  to  capture  on  the  surface. 

We  know  that  earthworms  have  been  land 
animals  from  very  early  times,  for,  though  no 


194  THE  HAUNTS  OF  LIFE 

actual  fossils  have  been  found,  as  they  have  no 
hard  parts  which  could  have  been  preserved, 
yet  we  have  evidence  of  the  existence  of  worms 
in  the  remote  past  "by  the  discovery  of  the 
trails  which  they  have  left  in  crawling  over 
soft  mud,  now  hardened  into  shale  or  slate,  or 
by  the  burrows  which  they  made  in  sand,  which 
has  now  been  converted  into  sandstone  and 
quartzite.  .  .  ."  "Worm-burrows  and  trails 
are  among  the  oldest  fossils  yet  discovered." 


FIG.  19. — PERIPATUS. 
A  primitive  Air-breather,  antecedent  to  Centipedes  and  the  like. 

The  second  great  invasion  was  that  of  the 
Air-Breathing  Arthropods,  led  by  simple 
jointed-footed  animals,  well  represented  by 
a  "living  fossil,"  called  Peripatus,  an  old- 
fashioned  creature,  surviving  from  a  very 
different  world.  Peripatus  is  a  beautifully 
coloured  soft-bodied  animal,  worm-like  in 
shape,  but  with  simple  stumpy  limbs,  with' 
antennae  on  the  head,  and  two  pairs  of  mouth- 
parts.  It  lives  chiefly  in  rotting  wood,  and 
comes  out  only  at  night.  When  it  is  handled  it 


THE  CONQUEST  OF  THE  DRY  LAND      195 

squirts  out  from  mouth-papillae  tiny  jets  of 
slime,  and  it  is  believed  to  do  this  also  as  a 
means  of  catching  small  insects.  Peripatus  is 
of  great  interest  to  naturalists,  because  in  some 
important  respects  it  resembles  a  worm,  while, 
in  others,  especially  in  the  possession  of  breath- 
ing tubes,  it  has  risen  to  a  higher  level,  and 
shows  relationship  with  insects.  It  must  be  very 
well  adapted  to  its  mode  of  life,  for  it  is  very 
widespread  in  warm  countries,  being  found, 


FIG.  20. — A  CENTIPEDE. 

with  slight  differences  between  the  species,  in 
Central  America,  the  West  Indies,  in  Chili,  in 
New  Zealand  and  Australia,  in  Asia,  in  Cen- 
tral Africa,  and  at  the  Cape  of  Good  Hope. 
The  second  great  invasion  led  on  to  centi- 
pedes, millipedes,  insects,  and  spiders,  and 
just  as  the  worm-invasion  resulted  in  the 
making  of  fertile  soil,  so  the  second  invasion 
had  for  its  great  consequence  the  establishing 
of  a  linkage  between  flowering  plants  and  the 


196  THE  HAUNTS  OF  LIFE 

flower-visiting  insects,  which  carry  the  fer- 
tilising golden  dust  or  pollen  from  blossom 
to  blossom.  This  is  certainly  one  of  the  most 
important  linkages  in  the  world. 

Darwin's  "  Cats  and  Clover"  Story. — In  his 
immortal  book,  The  Origin  of  Species  (1859), 
Charles  Darwin  told  the  story  of  the  connec- 
tion between  cats  and  clover — a  story  that  soon 
went  round  the  world.  It  is  a  very  familiar 
story,  but  it  should  not  become  trite  to  us,  for 
it  was  the  first  vivid  story  of  its  kind,  and  it 
was  told  by  the  greatest  of  all  naturalists. 

Darwin  took  one  hundred  heads  of  the  big 
purple  clover  and  put  muslin  bags  round 
them,  so  that  the  air  and  the  sunshine  could 
get  in,  but  no  humble-bees,  which  he  knew  to 
be  the  usual  visitors  of  the  clover.  From  these 
plants  he  got  not  a  single  seed,  while  from 
another  hundred  heads  close  by,  to  which  the 
bees  had  access,  he  got  27,000  seeds.  The  fer- 
tilising dust  or  pollen  which  the  bees  carry 
from  one  clover  blossom  to  another  makes  the 
possible  seeds  into  real  seeds,  that  is  to  say, 
embryo  plants.  A  nucleus  from  the  pollen- 
grain,  which  grows  down  the  pistil  of  the 
flower  to  the  ovules,  fertilises  an  egg-cell  in- 
side the  ovule,  and  as  this  develops  into  an 


THE  CONQUEST  OF  THE  DRY  LAND      197 

embryo-plant,  the  possible  seed  or  ovule  be- 
comes a  real  seed,  which  will  grow  into  a 
plant  when  it  is  sown.  So  the  more  humble- 
bees,  the  better  next  year's  clover  crop. 

But  the  nests  of  the  humble-bees,  which 
are  hidden  in  the  ground  or  in  a  mossy  bank," 
are  often  burglared  by  the  field-mice  or  voles, 
which  devour  the  white  grubs  of  the  bees.  So 
the  more  field-mice,  the  fewer  humble-bees. 

But  the  cats  on  the  prowl  kill  the  field- 
mice,  which  are  therefore  scarcer  near  vil- 
lages than  in  the  open  country.  The  cats  do 
not  appear  to  eat  the  field-mice,  but  they  kill 
them  for  sport.  So  the  more  cats,  the  fewer 
field-mice. 

One  may  perhaps  go  a  step  further  and  say: 
The  more  kindly  ladies  in  the  village,  the 
more  cats  there  will  be;  and  the  more  cats, 
the  fewer  field-mice;  and  the  fewer  field- 
mice,  the  more  humble-bees;  and  the  more 
humble-bees,  the  better  next  year's  clover  crop. 

In  any  case,  we  must  understand  that  the 
pollination  or  fertilisation  of  flowers  by  their 
insect-visitors,  a  linkage  established  after  the 
second  great  invasion,  is  one  of  the  most 
important  linkages  in  the  web  of  life.  For 
the  fertilising  dust  or  pollen  is  necessary  if 


198  THE  HAUNTS  OF  LIFE 

the  possible  seeds  are  to  become  real  seeds 
which  will  sprout.  And  even  when  the  pollen 
can  pass  from  the  stamens  of  the  flower  to  the 
pistil  of  the  same  flower  (self-pollination), 
the  results  are  not  usually  so  good  as  when 
the  pollen  is  carried  by  insects  (or  by  the 
wind)  from  one  blossom  to  another.  When 
there  is  cross-fertilisation  the  yield  of  seeds  is 
better.  And  the  plants  so  produced  tend  to 
be  more  variable,  which  will  be  a  good  thing 
if  it  is  useful  for  the  plant  to  change. 

The  Third  Great  Invasion. — It  was  about 
the  end  of  the  time  known  as  the  Devonian 
or  Old  Red  Sandstone  that  amphibians  made 
their  appearance,  and,  in  the  next  age,  the 
Carboniferous,  when  the  coal  measures  were 
laid  down,  they  had  their  golden  age.  These 
early  amphibians,  ancestors  of  our  frogs  and 
toads,  newts  and  salamanders,  were  the  ad- 
vance guard  of  the  third  great  invasion,  which 
eventually  led  to  the  appearance  of  reptiles, 
birds,  and  mammals.  This  third  invasion 
meant  the  opening  up  of  many  new  possibili- 
ties for  animals,  and,  in  the  long  run,  it  led 
to  man. 

It  is  interesting  to  notice  some  of  the  new' 
things  that  began  with  amphibians,  the  ad- 


THE  CONQUEST  OF  THE  DRY  LAND  199 

vance  guard  of  the  third  great  invasion.  They 
were  the  first  animals  to  have  fingers  and  toes 
(the  paired  fins  of  fishes  are  limbs,  but  they 
have  no  digits),  the  first  animals  to  have  a 
three-chambered  heart  (though  the  mud-fishes 
come  near  this),  the  first  animals  to  have  true 
lungs  (though  some  fishes  like  the  mud-fishes 
use  their  swim-bladder  to  help  them  in  breath- 
ing, and  it  is  no  doubt  the  forerunner  of  a 
lung),  the  first  animals  to  have  a  movable 
tongue,  and  the  first  backboned  animals  to 
break  the  silence  of  animate  nature  by  having 
a  voice. 

Besides  the  three  invasions  or  colonisations 
which  we  have  mentioned,  there  were  no 
doubt  others,  like  that  which  led  to  land-crabs 
and  wood-lice  (terrestrial  crustaceans),  or 
that  which  led  to  snails  and  slugs  (terrestrial 
molluscs). 

But  in  thinking  of  the  conquest  of  the  land, 
we  will  not  go  far  wrong  if  we  give  prominence 
to  the  idea  of  three  great  invasions — the  first, 
the  worm  invasion,  leading  to  the  making  of 
fertile  soil ;  the  second,  the  insect  invasion,  lead- 
ing to  the  linkage  between  flowers  and  their 
visitors;  the  third,  the  amphibian  invasion, 
leading  to  the  evolution  of  wits  and  of  love. 


200  THE  HAUNTS  OF  LIFE 

NEW  WAYS  OF  BREATHING 

The  colonisation  of  the  dry  land  by  aquatic 
animals  cannot  have  been  an  easy  task,  and 
our  question  now  is:  What  were  the  neces- 
sary qualifications? 

The  first  qualification  was  ability  to  capture 
the  oxygen  of  the  dry  air.  There  is  a  much 
larger  proportion  of  oxygen  in  the  air  than 
there  is  mixed  with  the  water,  but  it  is  not  so 
readily  available.  For,  mixed  with  the  water, 
it  seems  to  seep  in  very  readily  through  the 
delicate  moist  skin  of  the  general  surface  of 
the  body,  or  of  special  organs,  such  as  gills.  On 
one  side  of  the  membrane  there  is  water,  with 
oxygen  mixed  in  it;  on  the  other  side  of  the 
membrane  there  is  blood,  which  usually  car- 
ries a  pigment  with  a  strong  affinity  for  oxy- 
gen. What  happens  in  aquatic  breathing  is  that 
the  oxygen  diffuses  through  the  skin  into  the 
blood,  usually  entering  into  a  loose,  chemical 
union  with  the  blood-pigment.  With  its  cap- 
tured oxygen  the  blood  passes  to  the  living  tis- 
sues of  the  animal,  to  the  muscles,  for  instance, 
and  there  surrenders  its  oxygen  to  keep  up  the 
ceaseless  burning  (or  oxidation)  which  living 
implies.  As  the  result  of  the  combustion  (or 


THE  CONQUEST  OF  THE  DRY  LAND     20 1 


oxidation)  of  complex  carbon-compounds  in 
the  tissues,  the  waste  gas  CO2  (carbonic  acid 
or  carbon  dioxide)  is  formed,  which  is  col- 


202  THE  HAUNTS  OF  LIFE 

lected  by  the  blood,  and  got  rid  of  on  the  skin 
or  on  the  gills,  if  there  are  gills.  An  animal 
like  a  leech  is  a  good  example  of  cutaneous 
respiration,  simply  through  the  skin;  a  lob- 
worm or  a  lobster,  a  mussel  or  a  fish,  may 
illustrate  respiration  by  gills. 

But  getting  on  to  dry  land  involved  dry 
skins  and  protected  skins,  and  the  diffusing-in 
of  oxygen  was  no  longer  so  easy.  Thus  we 
find  various  devices  for  getting  the  air  into  the 
interior  of  the  body  and  for  spreading  out 
the  blood  on  internal,  not  external,  surfaces. 
Thus  insects  evolved  air-tubes,  carrying  fresh 
air  to  every  hole  and  corner  of  the  body — 
surely  part  of  the  secret  of  their  great  activity 
— and  amphibians  evolved  lungs,  probably 
transformations  of  the  swim-bladder  of  fishes. 
The  lowest  animals  to  show  the  red-blood- 
pigment  ( hamoglobin ) ,  which  we  and  all  back- 
boned animals  have,  were  certain  worms  called 
Ribbon-Worms  or  Nemertines,  which  live  for 
the  most  part  on  the  seashore.  The  virtue  of  this 
haemoglobin  is  that  it  captures  oxygen  very 
readily  from  outside,  and  parts  with  it  readily 
to  the  living  tissues,  and  it  is  certainly  interest- 
ing that  some  of  the  Ribbon-Worms  have  be- 
come terrestrial.  There  are  many  backboneless 
animals,  such  as  most  of  the  Arthropods  and 


THE  CONQUEST  OF  THE  DRY  LAND     203 

Molluscs,  that  have  no  haemoglobin,  but  some 
other  blood-pigment  (e.g.  haemocyanin)  not 
quite  so  good.  Yet  we  may  be  sure  that  the  se- 
cret of  making  haemoglobin  was  never  lost.  It 
was  too  good  to  lose.  If  haemoglobin  was  not 
always  continued  along  the  main  line,  where 
haemocyanin  often  took  its  place,  it  was  con- 
tinued on  side-lines  of  descent;  and  all  back- 
boned animals  have  red  blood.  A  pretty  case,  i 
illustrating  the  value  of  the  red-blood-pigment, 
is  that  of  the  "  blood-worms,"  which  are  some- 
times to  be  found  in  rain-water  barrels  and  in 
stagnant  pools,  where  the  oxygen  in  the  water 
is  very  scarce.  These  "  blood-worms "  are  the 
aquatic  larvae  of  certain  Harlequin-flies  (Chiro- 
nomus)  ;  they  are  called  "blood-worms,"  be- 
cause they  are  so  red;  the  redness  is  due  to 
haemoglobin,  which  few  insects  have;  the 
haemoglobin  is  present  in  "blood-worms,"  be- 
cause they  live  in  situations  where  oxygen  is 
very  scarce,  where  haemocyanin  is  hardly 
good  enough.  More  strictly,  perhaps,  we 
should  say  that  Harlequin-flies  are  insects 
with  red  blood,  and  that  this  makes  it  pos- 
sible for  their  larvae  to  live  in  very  foul 
water. 

The  land  animals'  new  way  of  breathing, 
notably  by  means  of  internal  surfaces,  like  the 


204  THE  HAUNTS  OF  LIFE 

breathing  chambers  of  land-snails,  where  the 
blood  is  spread  out  on  the  roof  of  a  cavity  con- 
taining air,  or  the  true  lungs  of  amphibians  and 
higher  vertebrates,  should  be  thought  of  in  con- 
nection with  the  fact  that  land  animals  tend  to 
become  thick-skinned,  or  to  acquire  some  sort  of 
protection  over  their  skin.  An  earthworm  is 
still  tender-skinned,  and  it  breathes  by  its 
skin;  a  frog  is  still  tender-skinned,  and  it 
breathes  partly  by  its  skin  all  through  its  life, 
and  wholly  by  its  skin  in  winter.  But  in  the 
scaly  reptiles,  in  the  feathered  birds,  and  in 
the  thick-skinned  mammals,  usually  well-pro- 
tected besides,  all  trace  of  skin-breathing  (or 
cutaneous  respiration)  has  vanished. 

CHANGES  IN  MOVEMENTS 

Animals  in  the  water  have  the  great  advan- 
tage of  universal  freedom  of  movement  in  any 
direction.  They  can  go  up  or  down,  forward  or 
backward,  to  right  or  to  left,  in  any  and  every 
plane.  But  land  animals  can  move  only  in  one 
plane — on  the  surface  of  the  earth;  and  this 
means  very  great  limitations  and  a  great  in- 
crease of  risks.  It  is  more  than  ever  necessary 
that  the  movements  should  be  quick  and  pre- 


THE  CONQUEST  OF  THE  DRY  LAND     205 

cise ;  fumbling  and  stumbling  are  fatal.  But  im- 
provement of  movements  means  a  more  com- 
plicated muscular  equipment  and  a  more  effec- 
tive controlling  (or  nervous)  system.  It  is  fair  to 
say  that  the  brain  was  the  controller  of  move- 
ments long  before  it  was  a  thinking  organ. 

We  do  not  mean  that  the  movements  of. 
aquatic  animals  are  not  admirable.  The  swim- 
ming fish  or  squid  cannot  be  surpassed.  We 
mean  that  the  freedom  of  movement  in  the 
water  allows  a  certain  leisureliness  (in  jelly- 
fishes,  for  instance)  which  is  impossible  on 
land,  unless  there  is  some  compensating  pe- 
culiarity, such  as  coming  out  at  night.  No  ani- 
mal moves  at  random,  but  the  water  animal 
has  a  wider  range  of  alternatives  than  a  land 
animal.  And  it  is  not  only  that  land  animals 
are  confined  to  one  plane ;  unless  they  learn  to 
burrow,  or  climb,  or  fly,  they  have  to  follow 
their  food  with  a  new  strenuousness.  In  the 
open  sea,  the  deep  sea,  and  the  fresh  waters,  and, 
to  some  extent,  on  the  shore,  food  is  sometimes 
brought  to  the  hungry  animal,  but  it  is  very 
seldom  that  this  can  be  said  to  occur  on  land. 

It  must  be  noted,  however,  that  an  appren- 
ticeship to  quick,  precise  movements,  such  as 
land  animals  require,  was  probably  served  on 


206  THE  HAUNTS  OF  LIFE 

the  shore,  for  the  conditions  of  life  are  more 
than  half  terrestrial  when  the  tide  is  out. 

In  his  fine  introduction  to  Zoology,  called 
Animal  Life,  Professor  F.  W.  Gamble  gives  a 
vivid  picture  of  the  four  chief  kinds  of  animal 
locomotion.  He  takes  the  case  of  a  man  in  a  boat 
on  a  river,  who  can  make  headway  against  the 
current  in  four  ways.  ( i )  He  may  take  a  boat- 
hook  and,  fastening  it  to  the  roots  on  the  bank, 


FIG.  22. — A  JERBOA. 
A  leaping  Biped  belonging  to  the  Rodent  Order. 

pull  himself  forward.  So  does  a  star-fish  pull 
itself  up  a  rock;  so  does  a  leech  pull  itself  for- 
ward when  it  fixes  its  mouth.  This  is  the  pulling 
method.  (2)  He  may  take  a  pole,  or  an  oar  for 
that  matter,  and,  pressing  it  against  the  bed  of 
the  stream,  lever  himself  forward.  So  does 
the  beetle  push  its  legs  against  the  ground ;  so 


THE  CONQUEST  OF  THE  DRY  LAND     207 

does  the  crab  on  the  shore  lever  itself  along; 
so  do  we  when  we  walk.  This  is  the  punting 
method.  (3)  He  may  take  an  oar,  and,  going 
to  the  stern  of  the  boat,  he  may  press  the  water 
from  side  to  side,  displacing  masses  of  water 
in  a  regular  rhythm.  So  does  the  fish  grip  the 
water  with  the  posterior  part  of  its  body,  popu- 
larly called  the  tail,  and  thrust  the  water  away 
from  it,  first  to  one  side  and  then  to  the  other. 
So  does  the  whale  with  its  propeller-like  tail 
— a  propeller,  however,  that  does  not  go  round. 
This  is  the  sculling  method.  (4)  Or  the  man 
may  sit  down  on  the  seat  of  the  boat  and  take 
up  the  oars  and  row.  The  insect  called  the 
Water-Boatman  rows  on  the  water  with  its  third 
pair  of  legs;  the  turtle  rows  with  its  flipper- 
like  limbs,  and  the  penguin  with  its  flightless 
wings  and  with  its  feet  as  well.  Aquatic  birds, 
when  swimming,  row  with  their  feet;  some 
diving  birds  row  under  water  with  their  wings. 
Flying  birds  row  in  the  air  with  their  wings. 

Now  it  may  be  said  that  the  conquest  of  the 
dry  land  meant,  among  other  things,  that  the 
punting  kind  of  locomotion  became  very  im- 
portant. It  was  learned  on  the  shore;  it  was 
perfected  on  dry  land.  Even  the  snake,  which 


208 


THE  HAUNTS  OF  LIFE 


is  often  described  as  rowing  upon  the  ground 
with  every  rib  for  an  oar,  is  perhaps,  more 


FIG.  23. — THE  AUSTRALIAN  COLLARED  LIZARD  (CHLAMYDOSAURUS). 
It  is  at  present  trying  to  be  a  Biped.     When  it  stands  at  bay,  it 
expands  its  Collar.    When  it  runs,  it  folds  its  Collar  back  on  its 
Neck.     (After  Saville  Kent.) 


accurately,  described  as  punting  with  many 
poles. 


THE  CONQUEST  OF  THE  DRY  LAND  209 

Except  in  the  case  of  some  sprawling  crea- 
tures, like  centipedes  and  snakes,  the  body  of 
a  land  animal  tends  to  be  compact.  The 
weight  has  usually  to  be  lifted  and  supported 
off  the  ground,  whereas  in  an  aquatic  animal 
the  weight  is  supported  in  the  water.  An 
animal  like  a  jelly-fish  is  unthinkable  on  land. 

NEW  WAYS  OF  LOOKING  AFTER  THE 
YOUNG 

The  conquest  of  the  land  necessarily  means 
new  ways  of  looking  after  the  eggs  or  the 
offspring.  For  the  aquatic  animal,  it  is  often 
enough  simply  to  liberate  the  eggs  into  the 
water,  which  .serves  as  their  soft  cradle;  but  it 
would  be  fatal  in  most  cases  if  a  land  animal 
merely  laid  its  eggs  or  its  young  ones  on  the 
ground.  They  would  be  dried  up  or  de- 
voured. So  we  find  many  ways  in  which 
safety  is  secured,  e.g.  by  burying  the  eggs  in 
underground  nests;  or  by  keeping  the  young 
ones  within  the  mother's  body  for  a  long  time 
before  birth,  so  that  they  are  not  very  helpless 
when  born;  or  by  carrying  them  about  after 
birth,  as  in  kangaroos  and  opossums. 

One  of  the  ways  of  securing  the  safety  of 


210  THE  HAUNTS  OF  LIFE 

the  eggs  or  the  young  ones  is  to  put  them  all 
in  a  hole  in  the  ground.  Earthworms  make 
a  little  barrel  of  hardened  slime  secreted  by 
the  "saddle"  or  swollen  girdle  on  their  body, 
and  as  this  slips  forward  it  carries  the  liber- 
ated eggs  with  it  and  closes  up  at  the  ends. 
We  find  it  sometimes  when  digging  in  the 
garden.  The  mother  trap-door  spider  makes 
a  well-finished  shaft  with  smooth  walls  and 
a  silk-hinged  lid,  and  lays  her  eggs  in  a  bunch 
at  the  foot.  The  crocodile  lays  her  eggs  in  the 
warm  earth,  sometimes  with  decaying  vege- 
table matter  round  about,  and  the  young  one 
calls  to  her  from  within  the  egg  when  it  is 
ready  to  be  hatched,  for  it  would  be  awk- 
ward to  be  born  2  feet  below  the  surface. 
Yet  that  is  what  happens  to  the  offspring  of 
those  mound-birds  that  dig  a  hole  in  the 
warm,  loose  volcanic  sand  of  the  beach  in 
Celebes.  The  mole's  nest  is  also  underground 
— a  grass-lined  chamber  below  a  big  mole-hill. 
Another  way  of  securing  the  safety  of  the 
eggs  or  the  offspring  is  to  hide  them  off  the 
ground  altogether.  Many  insects  lay  their 
eggs  in  or  on  leaves;  many  spiders  put  their 
eggs  in  a  silken  bag  or  cocoon  and  fasten  this 
between  two  leaves,  or  in  a  crevice.  Some 


THE  CONQUEST  OF  THE  DRY  LAND  211 

tree-toads  lay  their  eggs  in  a  damp  hole  in  a 
tree,  and  one  of  them  makes  a  leaf-nest  on 
branches  overhanging  the  water,  and  arranges 
matters  so  that  the  bottom  falls  out  and  lands 
the  contents  in  the  water  just  as  the  eggs  are 
turning  into  tadpoles.  The  harvest-mouse 
fastens  to  the  wheat  stems  its  lightly  built  nest 
of  twined  leaves  of  grass.  We  must  not  in- 
clude the  nests  of  animals  like  squirrels,  which 


FIG.  24. — THE  AUSTRALIAN  DUCKMOLE    (ORNITHORHYNCHUS). 
An  old-fashioned  Mammal  that  lays  two  eggs  in  a  well- 
hidden  nest  in  a  Burrow  beside  a  Pool. 

have  ceased  to  be  terrestrial  in  the  strict  sense, 
or  the  nests  of  flying  birds  and  thoroughly 
aerial  insects  like  wasps. 

A  third  way  of  securing  the  safety  of  the 
young  ones  is  to  keep  them  for  a  long  time 
within  the  shelter  of  the  mother's  body,  and 
perhaps  to  carry  them  about  after  they  are 


212  THE  HAUNTS  OF  LIFE 

born.  Thus  the  old-fashioned  Peripatus, 
which  we 'have  already  spoken  of,  carries  its 
young  one  for  a  year  before  it  is  born.  This 
means  that  the  young  Peripatus  is  able  to 
creep  about  soon  after  its  birth;  it  hides  itself 
under  the  mother's  body  and,  after  a  while, 
under  bark.  Just  in  the  same  way  among 
wild  horses,  which  must  always  be  on  the 
move,  the  foal  is  carried  by  its  mother  eleven 
months  before  birth,  and  the  result  is  that 
when  it  is  born  it  is  not  helpless  like  a  calf 
(which  is  hidden  in  a  thicket),  but  is  able 
very  soon  to  stagger  along  beside  its  mother. 
Among  aquatic  animals  there  is  in  many 
cases  a  long  larval  life ;  among  terrestrial  ani- 
mals the  young  are  often  born  as  miniature 
copies  of  their  parents  from  the  first.  This  is 
so  even  when  a  land  animal  is  quite  closely 
related  to  one  which  brings  forth  its  young  in 
the  water.  We  saw  that  the  young  mountain- 
salamander,  which  has  no  water  stage,  be- 
cause the  streams  are  too  swift,  is  born  like 
its  parent,  while  its  near  relative,  the  fire- 
salamander  of  the  plains,  which  goes  through 
the  early  stages  of  its  life  in  the  water,  begins 
as  a  tadpole,  and  passes  through  several 
changes  before  attaining  the  adult  form. 


THE  CONQUEST  OF  THE  DRY  LAND     213 

With  the  increasing  need  for  protecting  the 
young  there  has  grown  up  an  increasing  de- 
gree, not  only  of  parental  care,  but  of  parental 
affection.  The  highest  expression  of  this  is 
found — if  we  leave  the  birds  out  of  account — 
among  the  Mammals,  that  great  class  which 
includes  forms  so  different  as  Man,  the  mon- 
keys, the  carnivores,  the  hoofed  animals,  the 
gnawers,  besides  the  aerial  bats  and  the  ma- 
rine whales.  All  these  animals  have  one  great 
point  of  resemblance  to  which  they  owe  their 
name  of  Mammal — the  young  are  fed  for  the 
first  period  of  their  lives  on  the  milk  of  the 
mother.  The  period  of  suckling  varies  greatly 
in  length.  The  little  harvest-mouse,  the  small- 
est but  one  of  our  four-footed  beasts,  makes  an 
egg-shaped  nest  by  splitting  stalks  of  grass  or 
corn  and  weaving  them  firmly  together.  The 
nest,  which  usually  hangs  from  a  corn-stalk, 
is  lined  with  soft  leaves,  and  in  this  comfort- 
able home  the  young  ones,  eight  or  nine  at  a 
birth,  are  brought  forth,  and  are  suckled  by 
the  mother.  But  she  only  allows  them  this 
luxurious  life  for  a  week  or  two  till  they  are 
able  to  see  and  to  stand  on  their  own  legs. 
Then,  we  are  told,  she  takes  them  out,  "  gives 
them  a  little  practical  instruction  in  the  art 


214  THE  HAUNTS  OF  LIFE 

of  living,  and  hard-heartedly  drives  them 
away."  As  she  will  have  four  or  five  more 
litters,  all  equally  large,  before  the  summer 
is  over,  we  can  easily  understand  that  she  has 
not  much  time  to  spend  over  the  nursing  and 
education  of  each  set  of  babies. 

In  many  of  the  larger  mammals  the  time  the 
young  take  to  develop  within  the  mother  and 
the  time  of  their  helplessness  after  birth  are 
very  long,  and  it  is  among  these  that  we  find 
parental  affection  at  its  best.  It  is  not  merely 
mother-love — the  mouse  has  that,  though  only 
for  a  short  time.  Both  parents  show  affection 
for  their  children,  and  their  common  care  for 
them  has  often  led  to  lasting  affection  for  each 
other.  The  lion  hunts  along  with  his  mate  dur- 
ing the  breeding-season,  but,  as  soon  as  she  be- 
comes unable  to  accompany  him,  he  hunts  for 
her,  bringing  his  kill  to  the  den,  and  letting 
her  satisfy  her  hunger  before  he  takes  his  own 
meal.  From  the  time  the  cubs  are  weaned  until 
they  are  able  to  hunt  for  themselves  he  kills 
for  them  too,  and  when  they  are  able  to  go  out, 
which  is  not  till  they  are  almost  a  year  old, 
both  parents  go  with  them  to  teach  them  their 
business  in  life.  Both,  but  especially  the  lioness, 
will  defend  the  cubs  fiercely  from  any  danger, 


THE  CONQUEST  OF  THE  DRY  LAND   215 

and  at  this  stage  they  are  terribly  destructive, 
for  they  kill  anything  and  everything  that 
they  find,  whether  they  need  food  or  not,  and 
this  is  apparently  done  to  excite  the  cubs  so 
that  they  may  become  mighty  hunters  in  their 
turn.  The  cubs  remain  with  their  parents  till 
their  third  year,  when  they  leave  the  den,  but 
they  do  not  reach  their  full  growth  and 
strength  till  they  are  about  eight  years  old. 

When  parental  care  grew  strong  it  became 
unnecessary  to  have  the  multitude  of  offspring 
produced,  for  instance,  by  fishes,  which  may 
liberate  millions  of  eggs.  For  the  growth  of 
parental  care  secured  the  continuance  of  the 
race  with  comparatively  few  offspring.  But 
as  the  number  of  children  decreased  it  became 
possible  for  the  mother  to  know  them  all,  to 
see  more  of  them,  and  to  have  them  longer 
with  her,  and  all  this  meant  more  love.  And 
more  love  meant  more  care.  So  things  work 
round  in  a  beautiful  circle. 

Perhaps  this  argument  may  seem  very  diffi- 
cult, but  it  is  very  important.  Let  us  think  it 
over  again.  When  it  became  possible  for  ani- 
mals to  take  great  care  of  their  children,  it 
also  became  possible  to  have  quite  small  fami- 
lies without  there  being  any  risk  of  the  race 


216  THE  HAUNTS  OF  LIFE 

losing  its  place  in  the  sun.  The  cod-fish  has 
its  two  million  eggs,  and  there  is  terrific  infan- 
tile mortality;  the  golden  eagle  has  usually 
two  eggs  at  a  time,  and  the  eaglets  get  a  good 
start  in  life.  And  when  the  family  was  small 
and  the  parental  care  subtle,  the  parents  that 
were  at  once  good  and  clever  would  be  most 
successful.  A  race  with  selfish  and  stupid 
parents  would  tend  to  be  wiped  out. 

NEW  KINDS  or  PROTECTION. — There  is  an- 
other character  which  is  absolutely  necessary 
to  terrestrial  life.  Land  animals  must  be  able 
to  endure,  or  to  accommodate  themselves  in 
some  way  or  other,  to  considerable  differences 
of  temperature — between  sunlit  days  and  chilly 
nights,  between  hot  summers  and  cold  winters. 
We  ourselves  have  this  difficulty  to  face,  and 
we  solve  it  by  wearing  heavier  or  lighter  cloth- 
ing, and  by  heating  or  shading  our  houses 
according  to  the  weather.  But  we  are  alone 
in  doing  this;  Nature  has  found  different  an- 
swers to  the  puzzle  for  others  of  her  children. 

A  great  many  animals  which  find  abundant 
food  in  summer  grow  very  fat  in  autumn,  and 
this  coat  of  fat  serves  as  a  protection  against 
cold  and  against  scarcity  during  the  severer 
months.  The  coats  of  fur-bearing  animals" 


THE  CONQUEST  OF  THE  DRY  LAND     217 

become  longer  and  thicker  at  the  beginning 
of  winter,  and  the  hairs  fall  out  again  in 
spring.  The  same  kind  of  animal  may  have 
a  thicker  or  a  thinner  coat  according  to  the 
temperature  of  the  region  in  which  it  lives. 
The  tiger,  for  instance,  is  perhaps  commonest 
in  the  hot  jungles  of  India,  but  the  same 
species  spreads  far  north  to  very  high-lying 
and  very  cold  regions,  and  tigers  living  in  the 
north  have  much  thicker  and  longer-haired 
coats  than  those  in  the  south. 

A  very  effective  way  of  meeting  the  dangers 
of  a  cold  winter  after  a  warm  summer  is  to 
avoid  them  by  going  to  sleep.  This  is  called 
hibernating,  and  there  are  many  degrees  of  it. 
The  squirrel,  the  dormouse,  the  marmot,  and 
many  others  fall  into  a  light  slumber  in  their 
nests  beside  the  heap  of  nuts  and  fruits  they 
have  laid  in,  but  they  wake  up  and  have  a 
meal,  and  even  gather  in  a  few  more  stores 
whenever  the  sun  is  bright  and  the  day  warm. 

We  may  take  as  an  example  of  the  heavy 
sleepers  our  common  British  hedgehog.  When 
winter  approaches  he  chooses  a  hole  in  an  old 
wall,  or  under  a  hedge,  or  among  tree  roots, 
fills  it  with  withered  leaves,  buries  himself 
among  these,  rolls  up  into  a  tight  ball,  and  goes 


218  THE  HAUNTS  OF  LIFE 

to  sleep  for  the  whole  winter.  He  takes  no 
food  all  that  time,  but  he  is  not  moving,  his 
breathing  is  very  slow,  and  his  heart  beats  very 
slowly  and  feebly,  so  he  is  not  spending  much 
energy.  Life  is  at  a  very  low  ebb,  and  what 
waste  there  is,  for  there  can  be  no  life  without 
some  waste,  is  made  good  at  the  expense  of  the 
coat  of  fat  he  put  on  in  autumn.  Not  much  fresh 
air  gets  into  his  hiding-place,  so  the  carbonic 


FIG.  25. — SPINY  ANT-EATER  (ECHIDNA). 

A  primitive  egg-laying  Mammal.  The  egg  is  placed  in  a 
skin-pocket,  where  it  develops.  The  Spiny  Ant-eater 
illustrates  winter  sleep. 

acid  gas  given  off  by  his  feeble  breathing 
hangs  like  a  poison  cloud  all  round  him  and 
helps  to  keep  him  in  his  heavy  stupor.  An 
animal  in  this  state  has  often  been  compared 
to  a  fire  which  has  been  well  built  and  then 
banked  up  and  allowed  to  become  choked  with 
its  own  ashes.  Hardly  any  heat  is  given  off,  but 
as  long  as  a  red  glow  remains  in  the  centre  of 


THE  CONQUEST  OF  THE  DRY  LAND   219 

the  heap  we  can  revive  the  fire  by  stirring  it 
up  to  admit  air.  When  we  have  added  fresh 
fuel  and  cleared  away  the  ashes  it  will  burn  as 
brightly  as  ever  again.  So  with  the  winter 
sleeper.  When  the  first  warm  breath  of  spring 
penetrates  into  the  hedgehog's  hole,  he  gradu- 
ally awakens,  stretches  his  stiffened  limbs,  and 
creeps  forth  with  a  new  lease  of  life.  His 
breathing  quickens  as  his  lungs  fill  with  air, 
oxygen  is  carried  to  every  part  of  his  body,  the 
heart  beats  more  strongly  and  rapidly,  and  the 
now  hungry  hedgehog  begins  to  search  eagerly 
for  the  insects  and  worms  on  which  he  feeds. 

If  we  stir  up  our  resting  fire  too  suddenly  and 
let  in  too  much  air  at  once  the  glow  will  die 
out,  and  no  amount  of  fresh  fuel  will  re-kindle 
the  heap  without  fresh  fire.  Something  simi- 
lar sometimes  happens  to  the  lighter  sleepers 
if  they  have  been  roused  by  a  spell  of  mild 
weather,  and  a  hard  frost  sets  in  so  suddenly 
that  they  are  nipped  by  it  before  they  have  had 
time  to  settle  down  to  sleep  again.  But,  on  the 
whole,  hibernation  is  a  very  successful  device 
for  withstanding  great  changes  of  temperature. 

Another  way  of  meeting  the  winter  is  by 
putting  on  a  white  dress.  The  ptarmigan, 
which  is  rather  grouse-like  in  summer,  with  a 


220  THE  HAUNTS  OF  LIFE 

suit  of  grey  and  brown,  puts  on  a  white  plum- 
age when  the  winter  sets  in ;  and  the  chestnut- 
brown  stoat  becomes  the  white  ermine — snow- 
white  all  over  save  the  black  tip  of  the  tail. 
Now  this  white  dress  gives  its  possessor  a  gar- 
ment of  invisibility  against  a  background  of 
snow,  enabling  it  to  slink  upon  its  victims  and 
to  elude  its  enemies.  But  there  is  something 
more — perhaps  more  important.  For  a  warm- 
blooded animal  in  very  cold  surroundings  the 
dress  that  loses  least  of  the  precious  "animal 
heat"  of  the  body — the  heat  that  makes  it 
easier  for  the  chemical  process  of  the  body 
to  go  on — is  a  white  dress. 

We  must  not  follow  this  subject  further,  but 
it  is  interesting  to  think  out  some  of  the  other 
ways  in  which  land  animals  meet  the  difficul- 
ties of  the  winter.  What  are  the  expedients 
adopted  by  moles,  by  harvest-mice,  by  the 
mountain  hare,  by  squirrels,  by  the  curlews 
on  the  moor,  by  the  slow- worms,  by  the  frogs? 


BETWIXT-AND-BETWEEN  ANIMALS 

Of  great  interest  are  the  betwixt-and-between 
animals,  at  present  making  the  transition  be- 
tween water  and  dry  land.  On  many  tropical 


222 


THE  HAUNTS  OF  LIFE 


THE  CONQUEST  OF  THE  DRY  LAND   223 

has  true  vocal  organs,  the  "  scream,"  like  the 
fainter  "cry"  of  our  own  bullhead,  is  prob- 
ably the  sound  made  by  the  escape  of  air  from 
its  body.  For  both  Clarias  and  the  Climbing 
Perch  have  a  special  arrangement,  a  system 
of  tubes  branching  from  the  gill-chambers,  in 
which  air  is  stored,  so  that  the  fish  is  not  alto- 
gether dependent  on  its  gills. 

Land-crabs  illustrate  terrestrial  animals  in 
the  making.  In  warm  lands,  such  as  Jamaica, 
there  are  many  kinds,  often  living  in  forests 
far  from  the  sea,  sometimes  doing  great  dam- 
age in  the  sugar  plantations.  But  once  a  year 
they  assemble  in  enormous  numbers  to  make 
an  excursion  to  the  seashore  and  deposit  their 
eggs  below  high-water  mark,  where  they  leave 
them  to  be  swept  out  to  sea  by  the  tide.  Then 
they  return,  weary  and  spent,  to  their  inland 
haunt  for  the  rest  of  the  year. 

Darwin,  in  his  Naturalist's  Voyage  Round 
the  World,  gives  an  account  of  the  great 
Robber-Crab  which  occurs  in  the  Pacific 
Islands,  wherever  the  coco-nut  palm  grows. 
This  crab  belongs  to  the  same  group  as  the 
hermit-crab  of  the  seashore,  but  it  lives  in  a 
burrow  in  the  ground,  and  it  lines  it  with  the 
fibres  from  the  outside  of  the  coco-nut  shell. 


224 


THE  HAUNTS  OF  LIFE 


FIG.  27. — THE  ROBBER-CRAB  (BIRGUS  LATRO). 
Notice  one  climbing  up  a  Coco-palm. 


THE  CONQUEST  OF  THE  DRY  LAND     225 

The  Robber  grows  to  an  enormous  size,  being 
sometimes  a  foot  in  length,  and,  as  it  feeds 
entirely  on  the  pulp  and  milk  of  the  coco-nut, 
its  flesh  is  sweet  and  oily,  so  it  is  regarded  as 
a  dainty  by  the  natives  of  the  islands.  Darwin 
believed  that  the  Robber-Crab  only  picked  up 
the  fallen  nuts  from  the  ground,  though  it  was 
known  to  climb  trees,  but  a  later  observer  has 
not  only  seen  but  photographed  it  in  the  act 
of  picking  the  fruit  from  the  tree.  To  open 
the  nut  "  the  crab  begins  by  tearing  the  husk, 
fibre  by  fibre,  and  always  beginning  from  that 
end  under  which  the  three  eyeholes  are  situ- 
ated; when  this  is  completed  the  crab  com- 
mences hammering  with  its  heavy  claws  on 
one  of  the  eyeholes  till  an  opening  is  made. 
Then,  turning  round  its  body,  by  the  aid  of  its 
posterior  and  narrow  pair  of  pincers,  it  ex- 
tracts the  white  albuminous  substance." 

The  Robber-Crab  still  has  small  gills,  but 
its  gill-chamber  is  divided  into  two  parts,  and 
the  upper  part  is  able  to  breathe  dry  air.  Yet 
the  Robber-Crab  is  said  to  go  to  the  sea  at 
intervals  to  moisten  his  gills.  The  young  ones 
start  life  in  the  water  very  much  like  young 
hermit-crabs,  but  they  reach  maturity  by  a 
less  roundabout  path. 


226  THE  HAUNTS  OF  LIFE 

HAUNTS  WITHIN  HAUNTS 

Until  an  animal  becomes  big-brained  and 
resourceful,  or  is  endowed  with  a  rich  equip- 
ment of  inborn  gifts  which  we  call  instincts, 
or  has  some  special  ways  of  protecting  itself 
or  effacing  itself,  the  surface  of  the  earth  is  a 
hazardous  home.  This  makes  it  easy  to  un- 
derstand why  there  should  be  haunts  within 
haunts,  such  as  caves  and  grottos;  why  some 
land  animals  become  subterranean  burrowers 
and  others  arboreal  climbers;  why  some  have 
returned  to  the  water,  like  the  water-beetles 
and  the  whales;  and  why  some  have  sneaked 
inside  other  animals. 


BENEATH  THE  GROUND 

Among  the  first  animals  to  discover  the 
world  beneath  the  ground  were  the  earth- 
worms. The  strong  probability  is  that  they 
originally  belonged  to  a  fresh-water  stock,  for 
several  earthworms  have  gills.  When  they 
colonised  the  dry  land  and  became  able  to 
breathe  dry  air  through  their  moist  skin,  they 
must  have  had  for  a  time  a  Golden  Age. 
Land  vegetation  had  been  established,  and 


THE  CONQUEST  OF  THE  DRY  LAND  227 

they  found  food  enough  by  eating  the  soil  for 
the  sake  of  the  plant  remains  in  it,  and  by  col- 
lecting plant  crumbs  on  the  surface.  The 
more  they  worked,  age  after  age,  the  more 
soil  they  made,  and  the  more  plants  there 
were  with  crumbs  to  eat.  In  their  newly  dis- 


FIG.  28. — DIAGRAM  OF  SOME  BURROWERS. 

An  Earthworm  to  the  right,  a  Mole-cricket  to  the  left,  a 

Mole  in  the  middle. 

covered  country  below  the  ground  the  earth- 
worms lived,  if  not  in  ease,  at  least  in  safety. 
Meanwhile,  however,  evolution  was  in  prog- 
ress. The  second  great  invasion  of  the  dry 
land  had  occurred,  which  led  on  to  creatures 
like  centipedes  and  burrowing,  carnivorous 


228  THE  HAUNTS  OF  LIFE 

beetles,  both  of  which  began  to  trouble  the 
earthworms  in  their  retreats.  Ages  and  ages 
passed  and  the  third  great  invasion  occurred, 
which  led  on  to  creatures  like  burrowing 
blind-worms,  burrowing  slow-worms,  and, 
long  afterwards,  burrowing  moles.  And  so, 
to  cut  a  long  story  short,  the  earthworms 
which  once  were  so  safe,  having  discovered  a 
new  haunt,  are  among  the  most  persecuted  of 
animals.  So  they  have  become  nocturnal. 

When  one  begins  to  count  up,  one  finds  that 
the  number  of  subterranean  animals  is  much 
larger  than  one  at  first  supposed.  Mr.  Ed- 
mund Blunden  had  a  fine  vision  of  them  when 
he  wrote  his  "Gods  of  the  Earth  Beneath" 
( The  Waggoner,  and  other  Poems,  1920). 

"  I  am  the  god  of  things  that  burrow  and  creep, 
Slow-worms  and  glow-worms,  mould-warps  working  late 
Emmets  and  lizards,  hollow-haunting  toads, 
Adders  and  effets,  ground-wasps  ravenous: 
After  his  kind  the  weasel  does  me  homage, 
And  even  surly  badger  and  brown  fox 
Are  faithful  in  a  thousand  things  to  me." 


CAVE  ANIMALS 

The  animals  that  live  below  the  ground  are 
mostly  of  a  strenuous  nature.    The  mole,  for 


THE  CONQUEST  OF  THE  DRY  LAND     229 

instance,  is  one  of  the  strongest  of  all  animals. 
But  it  is  quite  different  with  most  of  the  ani- 
mals that  have  found  their  home  in  caves. 
Many  of  them  are  infirm,  many  are  weak- 
eyed,  many  are  nervous  and  delicate.  While 
we  admit  that  some  of  the  cave  animals  may 
have  degenerated  because  they  have  lived  so 
long  in  caves,  there  is  much  to  be  said  for  the 
view  that  most  of  the  cave  animals  took  to 
the  caves  because  they  were  weakly.  This  is 
borne  out  by  the  study  of  animals  that  have 
recently  become  cave-dwellers. 

ARBOREAL  LIFE 

Animals  owe  a  great  deal  to  plants.  In  the 
long  run  they  depend  on  plants  for  food ;  ani- 
mals use  the  munitions  which  plants  manufac- 
ture. Plants  prepared  the  earth  for  animals, 
making  it  friendly;  they  helped  to  secure 
moisture  and  soft  hiding-places.  They  formed 
a  subtle  sieve  against  which  animal  life  has 
often  beat,  with  the  best  of  results.  But  one 
of  their  crowning  benefits  was  in  providing 
animals  with  trees  to  climb  on.  We  some- 
times use  the  phrase,  "up  a  tree,"  to  suggest 
that  a  man  is  in  a  difficult  and  dangerous 


230  THE  HAUNTS  OF  LIFE 

situation,  but,  as  a  matter  of  fact,  getting  up  a 
tree  has  often  meant  a  progressive  step  in  the 
history  of  animal  life.  It  opens  up  new  pos- 
sibilities of  movement,  of  feeding,  of  nesting, 
and  so  forth,  and  it  is  a  portal  which  many 
different  kinds  of  animals  have  tried  to  enter. 
Even  earthworms  have  been  found  up  trees, 
and  the  land-leeches  often  drop  from  the 
branches.  Many  insects  and  spiders  are  ar- 
boreal, and  the  Robber-Crab  climbs  the  coco- 
palm  for  nuts.  The  skip-jack,  Periophthal- 
mus,  climbs  on  the  roots  of  the  mangroves, 
and  there  are  many  tree-toads.  Among  reptiles 
there  are  arboreal  lizards  like  the  chamaeleon, 
so  admirably  suited  to  the  branches  in  having 
a  prehensile  tail  and  both  its  hands  and  its 
feet  cleft  into  two  halves  for  gripping  pur- 
poses. Then  there  are  green  and  agile  tree- 
snakes.  Many  birds  and  mammals  are  strictly 
arboreal,  and,  in  the  case  of  monkeys,  the  per- 
fecting of  the  arboreal  habit  has  led  to  the 
emancipation  of  the  hand.  For  when  the 
fore-limb  was  no  longer  needed  as  a  support- 
ing member,  it  became  an  instrument  for 
touching  and  grasping,  for  handling  and  lift- 
ing. And  when  monkeys  got  a  free  hand  they 
also  got  a  nimbler  brain. 


4,     Cl 


CHAPTER  VI 
THE  MASTERY  OF  THE  AIR 

What  Getting  into  the  Air  meant  —  The  Flight  of  Insects  —  Why 
are  there  so  many  Insects?  —  The  Flying  Dragons  —  The 
Flight  of  Birds  —  Different  Kinds  of  Flying  in  Birds  —  Migra- 
tion the  Climax  —  The  Fourth  Solution  of  Flight  —  Fitnesses 
of  Birds  and  Bats  —  Attempts  at  Flight  —  Gossamer  Spiders. 


AjE  after  age  life  has  been  slowly  creeping 
upwards,  becoming  finer  and  finer  in  its 
forms,  and  with  greater  freedom  in  its  ways. 
And  who  shall  say  that  this  progress  is  going 
to  stop?  In  any  case  the  fact  is  that  for  mil- 
lions of  years  there  has  been  among  animals 
a  search  after  new  kingdoms  to  conquer,  some- 
times under  the  spur  of  necessity,  sometimes 
prompted  by  a  spirit  of  adventure.  So  after 
the  open  sea  and  the  shore  of  the  sea,  the  fresh 
waters  and  the  dry  land,  we  come  to  the  air. 
The  last  haunt  to  be  conquered  was  the  air. 
Of  course  there  are  no  animals  quite  aerial. 
These  dancing  May-flies,  they  spent  two  or 
three  years  as  aquatic  larvae  on  the  floor  of  the 
231 


232  THE  HAUNTS  OF  LIFE 

streams.  These  dragon-flies,  whose  mastery 
of  the  air  is  almost  perfect,  had  also  a  long 
aquatic  youth.  Perhaps  the  swift  comes 
nearest  a  thoroughly  aerial  creature,  for  it  is 
on  the  wing  from  dawn  to  dusk,  hawking  in- 
sects without  stopping,  except  to  deliver  its 
captures  at  the  nest,  never  coming  to  earth  at 
all — there  is  a  note  of  victory  in  its  shrill  cry! 
| 

WHAT  GETTING  INTO  THE  AIR  MEANT 

The  surface  of  the  earth  is  a  hazardous 
haunt,  but  getting  into  the  air  spells  safety. 
We  see  this  clearly  enough  in  the  chagrin  of 
the  cat  when  the  sparrow  rises  into  the  air  at 
the  last  moment,  after  all  the  stealthy  stalk- 
ing. It  must  be  very  disconcerting  to  be 
baulked  so  neatly.  Getting  into  the  air  means 
a  return  to  that  universal  freedom  of  move- 
ment which  animals  had  in  the  open  water. 

It  means  also  getting  off  the  ground  often 
arid  and  inhospitable,  a  power  of  rapid  pur- 
suit of  moving  food,  the  possibility  of  quickly 
passing  from  scarcity  to  plenty,  or  from 
drought  to  flowing  water.  It  has  led  to  an 
annihilation  of  distance  and  to  a  circumvent- 
ing of  the  seasons.  Last,  not  least,  getting  into 


THE  MASTERY  OF  THE  AIR        233 

the  air  means  new  opportunities  of  reaching 
suitable  places  for  laying  eggs  or  bringing  up 
the  young.  The  rooks'  nests  swaying  on  the 
tree-tops,  what  a  shrewd  ideal 

THE  FLIGHT  OF  INSECTS 

The  problem  of  flight  has  been  solved  four 
times  by  animals,  and  each  time  in  a  different 
way.  The  first  solution  was  that  discovered" 
by  insects.  In  insects  the  two  pairs  of  wings 
arise  as  hollow,  flattened  sacs,  which  grow  out 
from  the  upper  part  of  the  sides  of  the  body. 
They  arise  from  the  thorax  region  behind  the 
head,  a  region  with  three  rings  or  segments, 
each  bearing  a  pair  of  legs.  The  wings  grow 
out  from  the  second  and  third  rings  of  the 
thorax,  and  they  have  nothing  to  do  with 
limbs.  While  the  wings  of  a  bird  are  trans- 
formed fore-limbs,  the  wings  of  insects  are  on 
a  different  line  altogether;  but  we  do  not 
know  to  what  they  can  be  compared — they 
are  just  insects'  wings! 

The  insect's  body  is  very  lightly  built,  and 
the  secret  of  the  insect's  flight  is  the  extremely 
rapid  vibration  of  the  wings,  like  the  pro- 
peller of  an  airship.  A  watch  ticks  sixty 


234  THE  HAUNTS  OF  LIFE 

times  in  a  minute,  but  many  an  insect,  such  as 
a  humble-bee,  vibrates  its  wings  200  times  in 
a  second.  In  most  cases  the  hum  or  buzz  is 
simply  due  to  the  rapidity  with  which  the 
wings  strike  the  air,  and  there  is  no  structure, 
visible  to  the  naked  eye,  in  the  animal  king- 
dom that  moves  so  rapidly  as  an  insect's  wing. 
When  the  wings  are  large,  as  in  dragon-flies 
and  big  butterflies,  the  number  of  strokes  in  a 
second  is  small.  There  is  a  fossil  dragon-fly 
whose  wings  taken  together  have  a  span  of  2 
feet  from  one  side  to  another,  but  there  is 
nothing  like  this  to-day. 

Insects  vary  greatly  in  their  power  of  flight. 
Many  of  the  two-winged  insects  cannot  fly  more 
than  a  few  hundred  yards,  and  can  hardly  steer 
themselves  at  all,  but  are  borne  along  by  the 
wind.  This  is  true,  for  instance,  of  the  mos- 
quitoes, the  bite  of  which  in  some  countries 
often  causes  malarial  fever.  It  is  true  also  of 
our  common  house-fly,  which  may  cause  dis- 
ease such  as  typhoid  fever,  by  walking  on  our 
food  with  dirty  feet — for  it  revels  in  decaying 
matter,  and  may  come  straight  from  a  refuse- 
heap  to  our  jam-dishes  and  milk-jugs,  carrying 
with  it  disease-germs  which  find  there  highly 
favourable  conditions  for  multiplying  rapidly. 


THE  MASTERY  OF  THE  AIR         235 

It  is  useful  for  us  to  know  that  these  insects 
cannot  fly  far,  for  then  we  can  protect  our- 
selves to  a  great  extent  by  taking  care  that 
their  breeding-places — stagnant  water  in  the 
case  of  the  mosquito,  manure-  and  refuse- 
heaps  in  the  case  of  the  house-fly — are  not  in 
the  immediate  neighbourhood  of  our  dwell- 
ing-houses. 

But  many  other  insects  have  great  powers  of 
flight.  The  beautiful,  big,  rainbow-coloured 
or  sapphire-blue  dragon-flies,  which  are  so 
conspicuous  on  our  moors  in  sunny  weather, 
fly  all  day,  and  sometimes  cover  two  or  three 
miles.  They  catch  their  prey  of  smaller  insects 
on  the  wing,  and  can  suck  the  juices  from  them 
without  ceasing  to  fly.  Their  legs  have  be- 
come so  weak  that  they  are  of  no  use  at  all  for 
walking,  but  are  used  for  perching,  and  for 
catching  and  holding  the  prey.  The  bees,  too, 
as  we  may  see  for  ourselves,  are  capable  of 
strong  and  rapid  flight,  and  it  has  been  proved 
that  their  daily  business  of  honey-getting  may 
lead  them  several  miles  from  the  hive. 

The  power  of  flight  in  insects  sometimes 
rises  to  a  very  high  pitch.  A  wasp  has  been 
known  to  fly  tail-foremost  for  a  quarter  of  an 
hour  in  front  of  a  bicycle.  Dragon-flies,  which 


236  THE  HAUNTS  OF  LIFE 

gave  some  hints  to  the  early  makers  of  aero- 
planes, are  not  only  very  swift,  but  have  an 
astonishing  power  of  changing  their  direction 
instantaneously.  This  is  well  suited  for  catch- 
ing other  insects  on  the  wing.  Another  re- 
markable feature  in  the  flight  of  dragon-flies 
is  that  when  they  pass  from  a  sunny  to  a 
shaded  part  they  often  begin  at  once  to  prac- 
tise that  mysterious  kind  of  flight  called 
"soaring,"  so  well  seen  in  vultures  circling  in 
mid-air;  that  is  to  say,  they  continue  moving, 
but  without  any  visible  wing-strokes. 

There  is  no  end  to  the  interesting  peculiari- 
ties of  flight  in  different  orders  of  insects. 
Bees  and  their  relatives  have  microscopic 
hooklets  on  the  front  edge  of  the  hind-wings 
which  fix  on  to  a  bar  on  the  hind  edge  of  the 
fore-wings,  so  .that  the  two  wings  on  each  side 
act  as  one.  In  moths  and  butterflies  the  same 
result  comes  about  less  perfectly.  Beetles 
spread  out  their  heavy  fore-wings — too  heavy 
to  be  used  in  striking  the  air — and  clamp 
them  at  right  angles  to  the  length  of  the  body, 
so  that  they  serve  as  vol-planes  when  the 
lightly  built  hind-wings  strike  the  air.  In 
two-winged  flies  the  hind-wings  are  turned 
into  rapidly  quivering  "poisers,"  each  like  a 


THE  MASTERY  OF  THE  AIR        237 

stalked  half  dumb-bell ;  they  seem  to  be  sense- 
organs,  but  their  meaning  is  obscure. 

In  their  flight  insects  are  often  truly  admir- 
able, but  it  may  be  noticed  that  some  fly  only 
once  in  their  lifetime,  namely,  when  they  are 
starting  a  new  generation,  and  that  some  do 
not  fly  at  all.  The  simplest  of  all  insects,  the 
Spring-Tails  and  Bristle-Tails,  seem  never  to 
have  had  wings,  a  state  of  affairs  to  be  dis- 
tinguished from  what  is  seen  in  fleas,  which 
seem  to  have  lost  the  wings  their  ancestors 
had  long  ago.  The  flea,  as  every  one  is  pain- 
fully aware,  makes  up  for  its  loss  of  flight  by 
its  power  of  taking  extraordinary  leaps. 

The  leaping  powers  of  many  insects,  such  as 
grasshoppers  and  crickets,  suggest  the  theory 
that  insects  originally  used  their  wings  as 
parachutes  in  taking  skimming  leaps  along 
the  ground  or  from  branch  to  branch,  before 
they  were  able  to  use  them  to  strike  the  air  as 
organs  of  true  flight.  Just  as  a  creature  must 
walk  before  it  can  run,  so  perhaps  the  winged 
insect  had  to  jump  and  parachute  for  ages 
before  it  could  fly,  until  the  muscles  of  the 
wings  grew  strong.  The  fact  that  the  wings 
of  insects  often  contain  air-tubes  and  blood- 
spaces  suggests  that  they  originally  helped  in 


238  THE  HAUNTS  OF  LIFE 

respiration,  which  would  raise  the  pitch  of 
the  insect's  life. 


WHY  ARE  THERE  SO  MANY  INSECTS? 

Many  naturalists  estimate  the  number  of 
different  kinds  of  living  backboned  animals 
named  and  known  at  about  25,000.  But  of 
named  and  known  backboneless  animals  there 
are  ten  times  as  many,  and  the  most  of  these 
are  insects!  But  some  authorities  on  insects 
insist  that  this  computation  is  far  too  mod- 
**•  erate.  They  point  out  that,  on  the  average, 
6000  new  insects  are  discovered  every  year, 
and  insist  that  the  total  number  of  different 
kinds  now  living  on  the  earth  must  be  put  at 
over  2,000,000.  As  one  of  the  experts  says: 
"One  fact  remains  certain — namely,  that  the 
number  of  species  of  insects  is  at  least  six 
times  that  of  all  the  other  animals  put  to- 
gether." And  besides  the  prodigious  number 
of  different  kinds  of  insects,  there  is  the 
colossal  number  of  individuals  that  often  rep- 
resent a  particular  species  at  one  time.  Why 
are  there  so  many  insects? 

The  first  part  of  the  answer  is  that  most 
insects  have  the  power  of  true  flight,  which 


THE  MASTERY  OF  THE  AIR        239 

greatly  increases  their  safety,  their  chances  of 
getting  food,  their  possibilities  of  trekking 
and  migrating,  and  their  opportunities — so 
plain  in  the  wasp's  hanging  nest — of  laying 
their  eggs  or  nurturing  their  young  ones  in 
places  of  comparative  security,  far  from  the 
ground,  where  danger  always  lurks. 

The  second  part  of  the  answer  is  that  insects 
have  an  extraordinarily  successful  make-up. 
Thus  they  have  met  the  difficulty  of  captur- 
ing oxygen  by  developing  a  system  of  branch- 
ing air-tubes  (trachea],  carrying  oxygen  to 
every  hole  and  corner  of  the  body.  The  per- 
fect aeration  is  part  of  the  secret  of  the  in- 
sect's intense  activity  and  success.  The  blood 
never  becomes  impure.  Moreover,  the  beat- 
ing of  the  wings  helps  to  drive  the  used  air 
out,  letting  fresh  air  in.  Just  as  in  birds, 
which  are  also  very  successful,  the  flying  helps 
the  breathing. 

The  third  reason  for  the  great  success  of 
insects  is  to  be  found  in  their  remarkable  de- 
velopment of  instinctive  behaviour.  Along  a 
line  which  is  quite  different  from  intelligence, 
they  have  been  able  to  acquire  a  repertory  of 
ready-made  tricks,  an  inborn  ability  to  do 
effective  things  right  away  without  learning. 


240  THE  HAUNTS  OF  LIFE 

It  has  its  drawbacks,  this  instinctive  capacity, 
but  it  makes  for  success  as  long  as  the  unex- 
pected does  not  happen. 

The  fourth  reason  for  the  surpassing  success 
of  insects  in  the  system  of  animate  nature  is 
to  be  found  in  their  variability  or  plasticity, 
linked  with  that  of  the  plant  world.  While 
the  fundamentals  of  an  insect's  body  are  al- 
ways the  same,  the  details  vary  without  end, 
and  this  has  enabled  insects  to  find  an  unusual 
number  of  niches  of  opportunity,  especially 
in  their  vital  linkages  with  the  likewise  very 
variable,  flowering  plants.  Now,  the  more 
niches  of  opportunity  a  class  of  animals  can 
find,  the  greater  will  be  its  success. 

A  Russian  naturalist,  Chetverikov,  has 
called  attention  to  a  fifth  reason  for  the  suc- 
cess of  insects.  It  concerns  their  skeleton.  In 
backboned  animals  the  skeleton — of  living 
gristle  or  bone — is  inside  the  body;  in  insects 
and  other  jointed-footed  (Arthropod)  animals 
the  skeleton — of  not-living  chitin — is  outside 
the  body.  Now  it  is  argued  that  this  entirely 
different  kind  of  body  architecture  made  it 
possible  for  insects  to  become  very  minute 
without  ceasing  to  be  very  effective.  It  was 
more  practicable  to  become  small  when  the 


THE  MASTERY  OF  THE  AIR        241 

skeleton  consisted  of  external,  not-living,  du- 
rable but  elastic  chitin,  than  when  it  con- 
sisted of  internal,  living,  heavy  bone.  A 
mouse  is  a  mammoth  compared  with  a  midge. 
Insects  were  able  to  fill  minute  niches  of 
opportunity;  their  insignificance  became  their 
strength.  Most  of  the  very  large  insects  are 
extinct;  the  teeming  insect  world  of  to-day 
consists  in  the  main  of  small  creatures,  filling 
the  gaps,  as  it  were,  among  the  higher  ani- 
mals which  have  evolved  on  quite  different 
tacks.  So  we  understand  better  why  there  are 
so  many  insects  1 

THE  FLYING  DRAGONS 

The  second  solution  of  the  problem  of 
flight  was  discovered  by  the  extinct  Flying 
Dragons  or  Pterodactyls,  which  flourished  in 
Cretaceous  and  Jurassic  times.  They  varied 
from  a  sparrow's  size  up  to  a  spread  of  18 
feet;  and  their  wing  was  a  sheet  of  skin  spread 
out  on  the  enormously  elongated,  outermost 
finger,  which  is  usually  reckoned  as  corre- 
sponding to  our  little  finger.  They  probably 
clambered  about  the  cliffs,  and  how  far  they 
could  fly  we  do  not  know.  It  is  not  likely 


242  THE  HAUNTS  OF  LIFE 

that  they  were  adepts,  since  the  breastbone  has 
only  a  slight  keel  for  the  fixing  on  of  the 
wing-muscles;  and  we  know  that  in  birds  a 
prominent  keel  is  associated  with  highly  de- 
veloped flying  power,  whereas  the  running 
birds  like  the  ostrich  have  no  keel  at  all. 
On  the  other  hand,  the  Flying  Dragons 
show,  as  flying  birds  do,  a  solidifying  of  the 
middle  part  of  the  backbone,  giving  the 
wings  a  firm  fulcrum  against  which  to  work. 
It  is  probably  quite  safe  to  say  that  the 
Pterodactyls  represent  a  "lost  race";  they 
certainly  were  not  the  ancestors  of  birds.  It 
may  be,  however,  that  the  ancestors  of  the 
Pterodactyls  and  the  ancestors  of  our  birds 
were  related  to  one  another. 


THE  FLIGHT  OF  BIRDS 

The  third  solution  was  a  triumphant  one:  it 
gave  birds  their  mastery  of  the  air.  There 
seems  no  doubt  that  birds  sprang  from  an 
extinct  stock  of  Dinosaur  reptiles  which  had 
become  bipeds;  and  it  is  highly  probable  that 
they  were  to  begin  with  swift  runners  that 
flapped  their  scaly  fore-limbs  and  took  long, 
skimming  leaps  along  the  ground.  When 


THE  MASTERY  OF  THE  AIR         243 

scales  were  replaced  by  feathers,  no  one  knows 
how,  the  primitive  birds  probably  became 
arboreal,  and  served  a  long  apprenticeship  as 
parachutists,  launching  themselves  from  tree 
to  tree,  until  at  last  they  learned  to  soar  aloft. 
It  is  all  uncertain,  but  it  is  not  unreasonable 
to  suppose  that  before  birds  became  true  fliers, 
they  were  swift  runners  of  spare  build,  with 
light  bones,  a  strong  heart,  very  rich  blood, 
a  hot  skin,  a  power  of  keeping  up  an  almost 
constant  body-temperature,  a  very  good  di- 
gestion, a  fine  brain,  and  the  further  great 
advantage  that  the  flapping  of  the  wings,  even 
before  true  flight  was  fully  attained,  helped 
the  breathing.  A  bird's  body  is  a  bundle  of 
fitnesses,  well  suited  for  flight,  but  it  is  in- 
teresting to  inquire  whether  the  excellent 
qualities  of  birds  may  not  have  been  acquired 
before  they  became  fliers.  But  it  is  difficult 
to  do  more  than  inquire;  we  cannot  roll  back 
the  ages  and  see.  We  are  not  even  sure 
whether  the  Running  Birds  of  to-day  (the 
African  Ostrich,  the  South  American  Rhea, 
the  Australasian  Emu  and  Cassowary,  and  the 
Kiwi  of  New  Zealand)  are  the  descendants 
of  rather  primitive  birds  which  never  attained 
to  flight,  or  of  flying  birds  which  have  lost 


244  THE  HAUNTS  OF  LIFE 

their  flying  powers.  Just  as  whales  are  the 
descendants  of  land  mammals  which  went 
back  to  the  sea  ("  secondarily  aquatic  ") ,  so  the 
Running  Birds,  with  no  keel  on  their  breast- 
bone and  no  vane  in  their  feathers,  may  be  the 
descendants  of  flying  birds  which  went  back 
to  the  ground  ("secondarily  terrestrial"). 

There  is  a  deep  difference  between  the  wing 
of  a  bird  and  the  wing  of  a  Flying  Dragon 
or  the  wing  of  a  bat — a  deep  difference  in 
spite  of  the  fact  that  all  three  are  transformed 
fore-limbs.  In  the  Flying  Dragon  and  the 
bat  the  wing  is  what  is  called  a  patagial  wing 
or  web-wing,  for  what  strikes  the  air  is  a 
drawn-out  sheet  of  skin.  But  although  the 
bird  shows  a  little  patagium  or  web  stretched 
in  front  of  its  wing,  the  whole  secret  of  the 
bird's  wing  is  in  the  feathers,  borne  by  the 
arm  and  hand.  In  a  ship  the  air  strikes  the 
sails,  in  a  bird  the  sails  strike  the  air,  and  in 
the  bird  the  sails  are  the  feathers.  What 
made  the  bird's  flight  possible  was  the  growth 
of  feathers — feathers  with  the  barbs  united 
together  to  form  a  stiff,  but  elastic,  coherent 
vane  which  does  not  let  the  air  through  when 
they  press  against  the  air.  How  feathers 
began — perhaps  it  took  a  million  years  to  per- 


THE  MASTERY  OF  THE  AIR        245 

feet  them — no  one  knows;  but  they  have  the 
same  general  nature  as  scales,  and  perhaps 
they  may  be  thought  of  as  glorified  scales  or 
parts  of  scales. 

DIFFERENT  KINDS  OF  FLYING  IN  BIRDS 

In  the  ordinary  flight  of  a  bird  the  wings 
begin  vertically  above  the  back,  and  every  one 
is  familiar  with  the  "  clap  "  that  they  make  in 
pigeons  when  they  strike  one  another.  They  are 
drawn  forwards,  downwards,  and  backwards 
by  the  muscles  which  depress  the  wing,  the 
largest  of  which,  for  it  has  most  work  to  do, 
sometimes  weighs  half  the  whole  weight  of  the 
bird.  At  the  end  of  the  downstroke  the  wing 
is  pulled  up  again  to  begin  another  stroke. 
To  describe  a  complete  movement  four  ad- 
verbs are  required — forwards,  downwards, 
backwards,  upwards ;  and  the  tip  of  the  wing 
moves  through  a  complex  curve,  like  a  figure 
8  of  which  the  upper  part  is  much  the  larger. 

A  bird  is  lightly  built,  but  every  bird  is 
heavy,  and  if  it  be  killed  it  falls  to  the  ground 
with  a  thud.  As  Ruskin  said,  we  go  quite 
wrong  if  we  think  of  a  bird  as  like  a  buoyant 
balloon;  it  is  like  a  flying  bullet.  In  other 


246  THE  HAUNTS  OF  LIFE 

words,  the  bird  has  to  exert  itself  to  keep  up 
in  the  air.  In  the  stroke  of  the  wing  it  has 
to  displace — to  thrust  away  from  itself  down- 
wards and  backwards — a  mass  of  air  bigger 
than  its  own  body.  The  resistance  the  air 
offers  to  being  thrust  away  is  what  keeps  the 
bird  up. 

If  we  watch  birds  we  see  that  the  first 
strokes  of  the  wings  in  lifting  the  body  cost 
them  much.  A  Great  Northern  Diver  cannot 
rise  off  the  ground  at  all,  though  by  getting 
some  weigh  on  by  swimming  rapidly  it  can 
launch  itself  clean  out  of  the  water.  We  often 
see  a  cormorant  taking  a  little  run  along  the 
rock  to  get  up  speed  enough  to  enable  it  to  rise. 
Even  after  it  has  got  launched  in  the  air  it 
often  strikes  the  water  again  and  again.  Birds 
like  to  start  from  a  vantage-point,  and  a  pigeon 
gets  woefully  tired  if  it  has  to  start  many 
times  in  quick  succession  from  the  ground. 
But  note  the  important  point:  Ce  n'est  que  le 
premier  pas  qui  coute;  once  the  bird  has  got 
up  a  certain  velocity  in  the  air,  the  effort  re- 
quired to  keep  itself  up  becomes  beautifully 
less.  Sir  Isaac  Newton  showed  that  it  decreases 
in  proportion  to  the  square  of  the  velocity, 
and  this  is  a  very  important  fact.  If  there  is 


THE  MASTERY  OF  THE  AIR        247 

no  wind  against  the  bird  and  if  the  bird  is  not 
rising,  the  work  of  rowing  with  its  wings  in 
the  elastic  air  is  not  hard.  A  ship  has  the 
advantage  that  it  floats  in  the  water,  whereas 
the  bird  cannot  float  in  the  air;  but  the  ship 
has  the  disadvantage  that  the  water  offers  con- 
siderable resistance  to  a  body  passing  through 
it,  whereas  the  air  offers  little  resistance  to  a 
smooth  body  passing  quickly  through  it. 

The  second  kind  of  flight  is  gliding,  seen 
when  a  bird,  having  got  up  a  certain  speed, 
rests  on  its  oars,  and  holding  its  wings  taut 
glides  along,  or  when  a  bird  launches  itself 
from  a  tree  and  with  outstretched,  but  un- 
moving  wings,  glides  to  the  ground.  When  a 
bird  glides  along  after  getting  up  speed  it  is 
bound  to  sink,  but  this  may  be  counteracted 
for  a  time  if  an  ascending  current  of  air  beats 
up  against  the  bird's  outstretched  wings  from 
below.  We  often  see  this  when  a  gull  flying 
from  the  fields  seawards  meets  just  above  the 
edge  of  the  cliffs  an  ascending  landward 
breeze.  In  this  case  there  is  a  transition  to 
the  third  kind  of  flight,  called  "sailing." 

SAILING  FLIGHT. — When  an  albatross  goes 
up  one  side  of  the  ship,  keeping  pace  with 
the  vessel,  without  a  stroke  of  its  wings,  we 


248  THE  HAUNTS  OF  LIFE 

see  a  marvellous  thing,  but  the  marvel  in- 
creases when  in  front  of  us  the  bird  tilts  its 
body  and  turns,  and  comes  towards  us  down 
the  other  side  of  the  ship,  and  all,  so  far  as 
we  can  see,  without  a  stroke  of  its  wings.  This 
sailing  is,  we  think,  the  most  wonderful  loco- 
motion in  the  world,  and  the  puzzle  of  it  does 
not  seem  to  have  been  altogether  solved.  It  is 
finely  illustrated  by  vultures  "soaring"  in 
mid-air,  describing  circle  after  circle,  ascend- 
ing in  a  magnificent  spiral  and  sailing  down 
again,  and  all,  so  far  as  the  field-glass  shows, 
without  any  stroke  of  the  wings.  The  word 
"soaring"  is  often  applied  to  this  mysterious 
kind  of  flight,  but  "sailing"  is  a  better  word. 
It  is  better  to  keep  "soaring"  for  the  ascend- 
ing flight  of  the  lark,  where  there  is  very 
rapid  up-and-down  movement  of  the  wings, 
without  any  backward  stroke.  This  leads  on 
to  the  "hovering"  of  the  kestrel,  where  the 
up-and-down  movements  of  the  wings  are 
extraordinarily  rapid,  and  to  the  "fluttering" 
of  a  humming-bird,  poised  like  a  moth  before 
a  flower.  But  sailing  is  a  different  matter. 

Sailing  is  seen  in  birds  with  a  large  wing- 
area  or  sail-area  in  proportion  to  the  size  and 
weight  of  the  rest  of  the  body,  e.g.  albatross, 


THE  MASTERY  OF  THE  AIR        249 

vulture,  gull,  raven.  It  is  seen  only  when 
there  is  some  breeze,  but  there  may  be  consid- 
erable wind  overhead  when  there  is  little  or 
none  near  the  ground.  For  long  intervals  there 
are  no  ordinary  strokes  of  the  wings,  though  it 
is  a  bold  thing  to  assert  that  the  wings  are  not 
moving  at  all.  It  is  often  associated  with  a 
tilting  of  the  body,  which  can  be  effected  by 
movements  of  head  and  neck,  shoulder-joint, 
and  tail.  It  is  not  due  to  massive  up-currents 
of  air  playing  upon  the  under  surface  of  the 
bird,  for  it  is  sometimes  exhibited  when  light 
objects  like  feathers  are  seen  sinking  slowly  in 
the  air.  It  is  highly  probable,  however,  that 
the  sailing  bird  takes  advantage  of  horizontal 
currents  of  unequal  velocity  in  the  air.  It  is 
also  highly  probable  that  the  bird  having  got 
up  some  speed  by  strong  strokes  sustains  this 
velocity  against  the  wind  and  rises  in  its  sail- 
ing; that  it  turns  and  comes  down  with  the 
wind,  getting  up,  without  strokes,  sufficient 
speed  to  rise  again.  In  other  words,  it  is  con- 
tinually changing  "energy  of  position"  into' 
"energy  of  motion,"  and  conversely. 

It  is  important,  we  think,  to  remember  one's 
own  experience  in  such  an  exercise  as  skating, 
that,  given  a  certain  speed,  slight  movements 


250  THE  HAUNTS  OF  LIFE 

of  the  body,  to  one  side  or  the  other,  bending 
and  straightening,  may  be  very  effective  al- 
though there  is  no  actual  movement  of  the 
legs.  Experienced  mountain-climbers  are  also 
aware  of  the  importance  of  slight  adjustments 
which  are  eventually  made  almost  without 
thinking.  In  any  case  we  are  probably  safe 
in  saying  that  the  sailing  albatross  is  not  be- 
having like  a  kite. 

MIGRATION  THE  CLIMAX 

The  crowning  advantage  of  the  power  of 
flight  in  birds  was  that  it  enabled  them  to  mi- 
grate, to  evade  the  difficulties  of  the  winter.  In 
north  temperate  countries  the  great  majority 
of  the  birds  show  this  seasonal  mass-movement 
between  a  nesting-place  and  a  resting-place, 
the  former  being  always  in  the  colder  part  of 
the  range.  It  is  remarkable  in  many  ways,  this 
migration  of  birds  (see  our  Wonder  of  Life 
(1914)  and  Biology  of  the  Seasons  (1911))  ; 
it  occurs  in  such  a  punctual,  orderly  way;  it 
is  such  an  intense  activity,  for  many  migrants 
seem  to  keep  up  for  hours  on  end  a  speed  of  a 
mile  a  minute;  it  means  such  an  annihilation 
of  distance,  for  the  Pacific  Golden  Plovers  of 


THE  MASTERY  OF  THE  AIR         251 

Hawaii  seem  to  think  nothing  of  setting  out 
for  Alaska;  it  means  some  sense  of  direction 
that  we  do  not  understand,  for  a  young  bird 
that  has  never  been  more  than  a  few  miles 
from  home  will  start  gaily  in  the  autumn  for 
tropical  Africa  and  will  reach  its  goal  in 
safety,  and,  what  is  more,  will  sometimes 
come  back  again  the  following  spring  to  the 
precise  place  of  its  birth. 

THE  FOURTH  SOLUTION  OF  FLIGHT 

The  fourth  solution  of  the  problem  of  flight 
was  discovered  by  bats.  In  its  idea  it  is 
nearest  that  of  the  Flying  Dragons,  but  it  is 
quite  independent  and  by  itself.  Bats  are,  of 
course,  true  mammals,  covered  with  hair,  and 
giving  milk  to  their  offspring.  They  are  most 
nearly  related  to  the  Insectivores,  such  as 
shrew  and  mole,  and  it  is  interesting  to  notice 
that  there  is  in  the  Far  East  an  aberrant  in- 
sectivore  called  Galeopithecus,  placed  by 
some  authorities  in  a  special  order,  which  has 
a  sheet  of  skin  stretched  between  fore-  and 
hind-limbs,  and  is  a  very  expert  parachutist. 

The  wing  of  the  bat  is  formed  of  a  fold  of 
skin,  which  usually  begins  at  the  shoulder  and 


252  THE  HAUNTS  OF  LIFE 


FIG.  29.— WINGS  OF  DRAGON  (A),  BAT  (B),  BIRD  (C). 


THE  MASTERY  OF  THE  AIR        253 

stretches  along  the  upper  margin  of  the  arm 
to  the  hand.  The  thumb,  which  is  small  and 
clawed,  is  left  free,  but  the  membrane  stretches 
across  all  five  palm-bones  and  to  the  very  tips 
of  the  four  very  long  outspread  fingers,  and 
from  them  to  the  legs.  The  knees  are  turned 
outwards  and  backwards  like  our  elbows,  to 
meet  the  membrane,  which  reaches  down  to 
the  ankles,  leaving  the  feet  free,  but  filling  the 
space  between  the  hind-legs,  and  including  all 
the  tail  except  its  tip.  The  span  of  the  out- 
stretched wings  varies  from  2  inches  to  5  feet. 
This  wing  membrane  is  a  very  wonderful 
thing.  On  a  dead  bat  it  looks  like  a  piece  of 
dryy  tough  skin,  but  it  is  in  reality  so  well  sup- 
plied with  nerves  and  blood-vessels  that  it  is 
exquisitely  sensitive.  The  bat  is,  in  the  most 
literal  sense,  alive  to  its  finger-tips,  for  the 
sense  of  touch  in  the  whole  of  its  wing  is 
extraordinarily  delicate.  When  it  gets  into  a 
room,  as  it  often  does,  for  light  seems  to  at- 
tract it,  it  will  fly  round  and  round  without 
ever  knocking  against  wall,  cornice,  or  ward- 
robe, and  out  of  doors  will  pass  in  and  out 
among  the  branches  of  a  tree  without  coming 
in  contact  with  them,  because  of  its  power  of 
feeling  things  before  it  touches  them.  Its 


254  THE  HAUNTS  OF  LIFE 

mouse-like  ears,  and  the  curious  leaves  of  skin 
about  its  nostrils  are  also  very  sensitive,  but  it 
scarcely  seems  to  need  these  to  show  it  what  to 
avoid  when  flying.  Some  say  that  as  the  bat 
flies  it  utters  its  high-pitched  cry,  and  that  the 
echoes  of  this  from  branches  and  the  like  help 
it  to  avoid  obstacles.  , 

On  the  ground  the  bat  is  very  clumsy  and 
can  only  shuffle  along,  as  indeed  we  should 
expect  from  the  fact  that  both  fore-  and  hind- 
limbs  are  taken  up  in  the  making  of  the  wing. 

All  the  bats  in  Britain — and  there  are  about 
fifteen  different  kinds — belong  to  the  smaller 
insect-eating  section.  They  remain  in  retreat 
by  day,  but  on  mild  evenings  they  may  often 
be  seen  flying  about  in  pursuit  of  the  gnats, 
flies,  and  moths  on  which  they  feed.  The 
commonest  of  our  bats,  which  is  also  the 
smallest,  is  known  as  the  pipistrelle.  Its  body, 
covered  with  reddish-brown  fur,  is  only  about 
i^4  mch  in  length,  but  the  expanse  of  wing 
makes  it  look  much  bigger  in  the  air. 

As  cold  weather  approaches  and  insect  life 
gets  scarce,  the  bats  retire  to  winter  quarters. 
A  cave,  a  disused  chimney,  the  roof  of  a  barn, 
a  church  tower,  a  hollow  tree — any  dark,  quiet 
spot  will  serve  their  purpose.  Like  other 


PLATE  XIV. — BATS  FLYING  IN  THE  TWILIGHT. 


THE  MASTERY  OF  THE  AIR        255 

hibernating  animals,  they  have  stored  up  as 
much  nourishment  as  possible  within  their 
bodies  before  laying  themselves  up  for  the 
winter,  and  now  they  hang  by  their  toes  with 
their  heads  downwards  and  their  wings 
wrapped  about  them,  sleeping  comfortably, 
though  not  very  profoundly,  for  a  mild  spell 
will  wake  them  up,  until  spring  comes  round 
again.  Quaint  creatures  that  hang  them- 
selves up  by  their  toes  and  wrap  themselves 
up  in  their  arms! 

The  young  ones,  usually  only  one  at  a  time, 
are  born  in  May,  and  by  Juty  they  are  able 
to  fly  with  an  uncertain  fluttering  movement 
that  makes  them  look  like  big  moths  in  the 
twilight. 

The  nature  and  abundance  of  their  food 
makes  it  unnecessary  for  our  British  bats  to 
fly  very  far,  but  some  of  the  larger  fruit-eating 
bats  of  warmer  countries  make  enormous 
daily  journeys  in  search  of  their  favourite 
fruits.  We  are  told  that  the  "  flying  fox,"  so 
called  from  the  foxlike  look  of  its  long,  red- 
furred  snout,  will  fly  many  miles,  and  even 
cross  an  arm  of  the  sea,  when  there  are  or- 
chards to  be  robbed.  The  young  one  attaches 
itself  firmly  to  its  mother's  breast,  and  so  can 


256  THE  HAUNTS  OF  LIFE 

be  carried  without  impeding  her  flight  Thus 
the  bats,  though  belonging  to  a  class  nearly 
all  of  the  members  of  which  live  on  land, 
have  become  thoroughly  adapted  to  aerial  life. 
In  insect-catching  bats  the  skin  is  continued 
from  the  hind-legs  to  the  well-developed  tail, 
and  this  "  inter-femoral  membrane "  forms  a 
very  useful  pouch.  For  when  the  bat  has 
caught  a  good-sized  insect,  such  as  a  night- 
flying  beetle,  the  difficulty  arises  of  crunching 
it  without  letting  it  go  from  the  grip  of  the 
jaws.  In  her  delightful  Wild  Animals  of 
Garden  and  Hedgerow  (1920),  Miss  Frances 
Pitt  points  out  that  the  bat  lowers  its  head  to 
its  skin-basket  and,  pressing  its  booty  against 
that,  can  crunch  it  comfortably  without  risk  of 
losing  what  it  has  gained.  During  this  process, 
which  is  quickly  over,  the  bat  tumbles  a  little 
in  the  air,  but  speedily  recovers  itself. 

FITNESSES  OF  BIRDS  AND  BATS 

Birds  and  bats  are  not  in  any  way  related  to 
one  another,  except  that  the  two  classes,  birds 
and  mammals,  may  be  traced  back  to  a  com- 
mon ancestry  in  extinct  reptiles.  It  is  all  the 
more  interesting  to  find  that  similar  fitnesses  or 


THE  MASTERY  OF  THE  AIR        257 

adaptations  for  flight  have  been  wrought  out  in 
the  bodies  of  bird  and  bat.  Both  are  lightly 
built  as  regards  their  skeleton,  which  means  a 
big  surface  for  fastening  muscles  on  to,  with- 
out great  increase  in  weight  Both  show  a  keel 
on  the  breastbone  for  the  better  fixing  on  of  the 
muscles  of  flight,  but  the  bat's  keel  is  much  less 
prominent  than  a  bird's.  Both  show  a  solidi- 
fying of  the  middle  region  of  the  backbone, 
which  affords  a  firm  fulcrum  for  the  wings  to 
work  against.  In  almost  every  other  respect 
they  are  as  different  as  different  could  be,  but 
it  may  be  noted  that  most  birds  and  most  bats 
are  small,  as  if  there  were  a  size-limit  to  flying 
creatures.  A  bird  like  an  albatross,  with  a  span 
of  1 1  feet  from  tip  to  tip  of  the  outstretched 
wings,  is  quite  out  of  the  common,  and  so  are 
the  very  large  fox-bats  of  the  Far  East. 

ATTEMPTS  AT  FLIGHT 

Apart  from  man,  the  problem  of  flight  has 
been  successfully  solved  four  times — by  in- 
sects, Pterodactyls,  birds,  and  bats;  but  how 
often  has  its  solution  been  attempted?  It  is 
very  interesting  to  study  these  attempts,  some 
of  them  splendid  failures. 


258  THE  HAUNTS  OF  LIFE 

(A)  There  has  been  much  discussion  over  the 
FLYING  FISHES,  whether  they  show  anything 
that  can  be  called  true  flight,  that  is  to  say, 
whether  their  fore-fins  strike  the  air  or  not.  The 
general  answer,  for  the  common  flying  fish, 
Exoc&tus  volitans,  which  one  sees  when  one 
crosses  the  Atlantic,  is  that  the  creature  takes 
a  great  leap  out  of  the  water,  using  its  tail  as 
propeller,  and  helped  perhaps  by  the  momen- 
tum of  a  wave;  that  it  holds  its  pectoral  fins 
taut,  without  more  than  slight  vibrations,  and 
uses  them  as  vol-planes,  not  as  wings;  that  it 
may  for  mechanical  reasons  rise  in  its  vol- 
planing, so  that  it  lands  on  the  deck  of  a  ship ; 
and  that  the  alteration  of  the  curve  of  move- 
ment is  in  the  main  involuntary,  being  due  to  a 
slight  tilting  of  the  body.  We  have  watched 
the  common  flying  fishes  with  care  and  we 
never  saw  anything  approaching  a  stroke  with 
the  fore-fins.  We  have  seen  them  cross  in  front 
of  the  prow  of  the  steamer  and,  in  the  course 
of  their  curve,  come  crashing  against  a  port- 
hole. The  leaping  is  often  a  desperate  attempt 
to  escape  from  their  enemy  the  tunny. 

In  regard  to  the  Flying  Gurnard  ( Dactyl  - 
opterus)  some  good  observers  have  described  a 
fluttering  of  the  pectoral  fins,  which  looks  like 


260  THE  HAUNTS  OF  LIFE 

the  beginning  of  flight,  and  there  is  no  reason 
why  this  should  be  called  impossible.  It  has 
to  be  remembered,  however,  that  though  the 
muscles  of  the  pectoral  fins  of  flying  fishes  are 
larger  in  proportion  than  in  related  fishes, 
they  are  not  much  larger.  It  follows  that 
there  cannot  be  much  striking  of  the  air.  At 
the  most,  there  is  only  a  beginning  of  flying. 
Recent  studies  of  flying  fishes  have  shown 
that  the  "flight"  differs  greatly  according  to 
the  atmospheric  conditions.  It  is  short  when 
the  air  is  still;  it  is  long  when  there  is  a 
breeze.  In  fact  the  " flight"  of  flying  fishes 
sometimes  approaches  the  "sailing"  of  the 
vulture  and  the  albatross. 

(B)  Another  attempt  has  been  made  by 
some  tree-toads,  which  take  flying  jumps  from 
branch  to  branch.    In  our  common  frog  there 
is  a  familiar  web  on  the  large  hind-feet,  which 
is    obviously    well    suited    for    striking    the 
water  in  swimming.     In  the  flying  tree-toad, 
Rhacophorus,   there   is   a   web   between   the 
fingers  as  well  as  between  the  toes,  and  thus 
the  animal  has  four  parachutes. 

(C)  There  is  something  fascinating  in  the 
little   Flying  Lizard,   Draco   volans,   of   the 
Malay  States,  which  has  gone  far  towards 


PLATE  XV. — FLYING  DRAGONS  (Draco  volans)  OF  THE  FAR  EAST. 
The  parachute  of  skin  is  spread  out  on  five  or  six  greatly  elongated  mobile 
ribs.     Note  the  upper  and  the  under  surface.     Also  how  the  parachute 
is  closed  in  when  the  animal — a  Lizard  after  all — rests  on  the  branch. 


THE  MASTERY  OF  THE  AIR        261 


FIG.  31. — FLYING  TREE-TOAD  (RHACOPHORUS). 


262  THE  HAUNTS  OF  LIFE 

flight  on  an  idea  of  its  own.  Like  all  other 
parachutists,  except  the  Flying  Fishes,  it  lives 
in  trees,  and  it  is  able  to  take  daring  leaps  from 
one  to  the  other.  It  has  five  of  its  ribs  much 


FIG.  32. — THE  LITTLE  FLYING  DRAGON   (DRACO  VOLANS) 

OF  MALAY. 

Note  the  Pendent  Pouch    (P)    on  its  Throat,   and  the 
Extended  Ribs   (R)    supporting  the  Parachute. 

elongated  and  very  movable,  and  they  carry 
out  between  them  a  sheet  of  skin.  When  the 
little  dragon  (Draco,  its  name)  is  resting  we  do 
not  notice  much  that  is  peculiar,  for  the  long 
ribs  fold  in  and  lie  parallel  with  the  backbone, 


THE  MASTERY  OF  THE  AIR         263 

like  a  collapsed  umbrella.  When  it  is  going  to 
"fly"  the  ribs  are  extended  and  form  the  sup- 
ports of  a  fine  parachute.  The  dragon  can 
swoop  several  yards,  sometimes  to  avoid  an 
enemy,  sometimes  after  a  swarm  of  insects.  The 
upper  surface  of  the  body  is  brightly  coloured, 
and  there  is  a  curious  dewlap  on  the  throat. 

There  is  another  tree-lizard,  Ptychozoon, 
whose  long  tail  bears  a  scolloped  fringe  of 
skin  on  each  side,  and  this  again  helps  in 
swooping.  There  is  a  tree-snake  (Dendrophis) 
which  disdains  all  accessories  and  launches 
itself  stiffly  from  a  lofty  branch  to  the  ground. 
But  is  there  anything  in  the  way  of  movement 
a  snake  cannot  do  except  cross  a  sheet  of  ice 
or  a  horse-hair  rope? 

(D)  What  bats  achieved  many  mammals 
have  attempted,  that  is,  if  we  regard  parachut- 
ing as  on  the  way  towards  flight.  It  is  note- 
worthy that  all  the  attempts  at  flight  among 
mammals  have  been  made  in  families  that  are 
arboreal  in  habit,  so  that  climbing  tall  trees 
may  have  been  the  first  step  towards  acquiring 
wings  or  some  substitute  for  them.  Thus  we 
have  the  flying  phalangers  of  New  Guinea  and 
Australia,  including  many  species, "  the  largest 
of  which  is  as  big  as  a  cat,  while  the  smallest 


264  THE  HAUNTS  OF  LIFE 

is  no  bigger  than  a  mouse."  All  of  them  live 
among  tall  trees  and  keep  hidden  in  the 
branches  till  evening,  when  they  become  very 
active  in  search  of  the  fruits,  leaves,  and  insects 
on  which  they  feed.  Their  flight,  too,  is  of  the 
parachute  order,  but  it  is  much  more  effective 
than  that  of  the  flying  lizard.  They  have  a  fold 
of  skin  covered  with  hair  extending  from  the 
fore-legs  to  the  hind-legs,  and,  when  they 
launch  themselves  into  the  air  from  the  top  of 
a  tree,  the  outspread  skin  bears  them  up  for  a 
considerable  distance,  and  even  enables  them 
to  change  their  direction  a  little  while  in  the 
air.  They  cannot,  however,  move  the  fold  of 
skin  up  and  down,  and  therefore  they  can  only 
"fly"  to  a  lower  level  than  they  started  from. 
The  "  flying  squirrels,"  mostly  found  in 
Asia,  have  a  somewhat  similar  arrangement, 
and  they  are  able  to  leap  a  distance  of  20 
yards.  The  curious  "  flying  lemur  "  or  Colugo 
of  the  Indian  Archipelago  has  an  even  more 
effective  parachute,  for  its  fold  of  skin  does 
not  stop  at  the  hind-legs  but  fills  the  space  be- 
tween them,  the  long  tail  passing  down  the 
middle.  Mr.  Wallace,  the  naturalist,  observed 
the  flying  lemurs  in  their  native  haunts,  and 
he  thus  describes  their  flight:  "Once  in  a 


THE  MASTERY  OF  THE  AIR         265 

bright  twilight  I  saw  one  of  these  animals  run 
up  a  trunk  in  a  rather  open  place,  and  then 
glide  obliquely  through  the  air  to  another  tree 
on  which  it  alighted  near  its  base,  and  immedi- 
ately began  to  ascend.  I  paced  the  distance 
from  one  tree  to  the  other,  and  found  it  to  be 
not  less  than  seventy  yards,  and  the  amount  of 
descent  I  estimated  at  not  more  than  thirty  or 
forty  feet,  or  one  in  five.  This,  I  think,  proves 
that  the  Colugo  must  have  some  power  of 
guiding  itself  through  the  air,  for  otherwise 
in  so  long  a  distance  it  would  have  little 
chance  of  alighting  exactly  on  the  trunk." 

An  interesting  point  in  regard  to  these 
parachuting  mammals  is  that  there  are  so 
many  which  seem  to  be  independent  of  one 
another.  It  is  worth  while  making  a  technical 
list,  because  it  shows  how  the  same  impulse 
must  have  become  urgent  over  and  over  again. 

^  (   Perhaps     to     be     ranked 

GALEOPITHECUS      .     .j       amoPng  the  Insectivores. 

ANOMALURUS  .  f  Amonf   the    ro.derf'  ,re' 

PETAURISTA   .     .     .     J       *a*ed . to    ^els    but 
SCIUROPTERUS          .     .]       d^ering  markedly  from 
(^      one  another. 

PETAURUS  .  .  .  .  (  All  of  them  Marsupials, 
PETAUROIDES  .  .  .  .  -j  but  not  nearly  related 
AEROBATES  .  f  to  one  another. 


266  THE  HAUNTS  OF  LIFE 

THE  BALLOONING  SPIDERS 

In  these  parachutists,  some  of  which  have 
their  faces  set  towards  flying,  we  get  a  glimpse 
of  what  is  certainly  a  quality  of  living  crea- 
tures— the  quality  of  endeavour  and  experi- 
ment, of  insurgence  and  adventure.  We  can- 
not get  the  right  word  for  it,  because  it  is  a 
characteristic  of  life  itself,  asserting  itself  at 
many  levels.  We  find  it  among  the  simple 
primeval  creatures  of  the  Open  Sea,  which  do 
not  form  "bodies"  in  the  strict  sense,  but  ex- 
pend all  their  endeavour  in  fashioning  their 
single  "cell,"  so  that  it  is  often  like  a  fairy 
palace,  and  is  a  little  world  of  internal  micro- 
scopic complexity.  We  find  it  in  the  simple 
sedentary  creatures  of  the  shallow  water, 
whether  seaweeds  or  sponges,  zoophytes  or 
corals,  which  add  to  the  self-preservation  law 
of  the  firstlings,  as  Dr.  Church  says,  the  sec- 
ond great  law  that  no  race  will  continue  un- 
less the  individual  members  do  their  bit  in 
securing  its  continuance.  We  find  it  in  the 
instinctive  behaviour  of  ants  and  bees,  in  the 
instinctive  and  intelligent  behaviour  of  birds 
and  mammals,  in  the  instinctive,  intelligent, 
and  rational  behaviour  of  man. 


THE  MASTERY  OF  THE  AIR        267 

No  book  nor  naturalist  can  ever  come  within 
sight  of  the  end  of  the  study  of  the  haunts  of 
life,  but  as  we  must  close  these  studies  now,  we 
wish  to  finish  with  a  picture  which  may  serve 
as  an  emblem  of  the  quality  of  life  which 
seems  to  us  so  characteristic.  Our  picture  is  that 
of  the  Gossamer  Spider,  a  terrestrial  creature 
which  makes  aerial  journeys  without  wings. 

At  many  seasons  of  the  year,  but  in  the 
autumn  especially,  many  small  spiders  of 
various  kinds  mount  on  to  gateposts  and  the 
rails  of  wooden  bridges  and  tall  plants  like 
ragwort.  They  stand  with  their  head  to  the 
wind,  and  allow  threads  of  silk — four  is  a 
common  number — to  float  out  from  the  spin- 
nerets at  the  hind  end  of  the  body.  When 
these  are  long  enough  the  wind  grips  them, 
and  the  spider  lets  go,  usually  turning  upside 
down.  On  the  wings  of  the  wind,  supported 
by  the  silken  parachutes,  the  spiders  are  borne 
from  one  parish  to  another,  from  a  crowded 
place  it  may  be  to  a  free  place,  from  a  hungry 
land  it  may  be  to  a  land  of  plenty.  Sometimes 
they  are  borne  in  safety  over  a  sheet  of  water, 
though  the  tips  of  their  toes  may  touch  the 
surface  film.  If  the  wind  should  rise,  the 
ballooning  spider  can  wind  in  its  threads, 


268  THE  HAUNTS  OF  LIFE 


FIG.  33. — GOSSAMER  SPIDERS. 
On  their  Aerial  Journey. 


THE  MASTERY  OF  THE  AIR        269 

as  we  see  one  doing  when  it  reascends  the 
thread  by  which  it  has  lowered  itself  half- 
way from  the  roof.  If  the  wind  should  fall, 
the  spider  can  pay  out  more  thread.  It  is 
quaintly  like  the  sailor  furling  and  unfurling 
his  sails.  When  the  spiders  feel  they  have 
had  enough  of  aerial  journeying,  they  wind 
in  some  thread  and  sink  to  the  ground.  When 
ten  thousand  little  spiders  do  this  about  the 
same  time  there  is  what  is  called  a  shower  of 
gossamer.  The  countless  threads  are  seen  on 
the  hedgerow  and  on  the  ploughed  field  and 
on  the  lea,  and  if  we  kneel  down  and  look 
against  the  light  we  see  the  quivering,  glisten- 
ing maze — an  image  of  the  web  of  life  itself. 
But  what  impresses  us  most  is  the  simple  fact 
that  a  wingless  terrestrial  creature  journeys 
through  the  air.  It  has  attempted  the  appar- 
ently impossible  and  achieved  it.  We  are 
filled  with  a  reasonable  wonder  at  the  adven- 
turousness  of  life. 


INDEX 


Acorn-shells,  40. 

Collared  Lizard,  208. 

Aerial  animals,  231. 

Colour    of    deep-sea    animals, 

Aesop  Prawn,  51. 

129. 

Albatross,  247. 

Coral-reef,  6. 

Amphibians,  198. 

Crayfish,  158. 

Angler,  43,  93. 
Animal  locomotion,  206. 

Crumb  of  Bread  Sponge,  37. 

Arboreal  animals,  229. 
Argonaut,  100. 
Autotomy,  50. 

Darkness  of  deep  sea,  112. 
Deep-sea  fauna,  119. 
Diatoms,  68. 

Dog  whelk,  31. 

Bacteria,  147. 

Dragon-fly,  232,  234,  235,  236. 

Barnacle,  96. 

Dry  land,  185. 

Bat  skeleton,  257. 

Duckmole,  211. 

Bees,  235,  236. 

Beetles,  236. 

Ear-bones,  188. 

Bird  skeleton,  257. 

Earthworms,    193. 

Bitterling,  150. 

Eel,   141,   163. 

Blood,    188. 

Elver,  163. 

Blood-  worms,  203. 

Ermine,  220. 

Bracken,   148. 

Eyes  of  deep-sea  animals,  130. 

Breathing  of  insects,  239. 

Buckie,  29,  30. 
Bullhead,  161. 
Burrowers,  226. 
Butterfish,  13. 

Feathers,  244. 
Feather-stars,  121. 
Fishing-frog,  43. 
Flight  of  bats.  251. 

"   birds,  242. 

Camouflage,  51. 

"  insects,  223. 

Cats  and  Clover,  196. 

kinds  of,  245. 

Cave  animals,  228. 

Floating  barnacle,  96. 

Centipede,  195. 

Flounder,  142. 

"  Challenger  "   Expedition,   69, 

Flying  dragons,  241. 

106. 

fishes,  258. 

Circulation  of  matter,  28,  145. 

gurnard,  258. 

Clarias,  221. 

lemur,  264. 

Climbing  Perch,  221. 

lizard,  260. 

Cock-paidle,  56. 

"       phalanger,  263. 

270 

INDEX 


271 


Flying  squirrel,  264. 

Mackerel,  70. 

"       tree-toad,  260. 

Malaria,   151. 

Food-supply  of  deep  sea,  116. 

Marine  Lizard,   12. 

Fresh  Waters,  136. 

Masking,  48. 

Fresh-water  mussel,  149. 

May-flies,  179. 

snail,  151. 

Migration,  250. 

spider,  181. 

Mosquito,   151,  234. 

"            sponge,  155. 

Mother   Carey's   Chickens,   82. 

Frog,  177. 

Mudfish,   154. 

"      on  seashore,  13. 

Mudskipper,  222. 

Gaff  top-sail,  57. 

Nests,  210. 

Gill  clefts,  187. 
Glass-Rope-Sponge,  123. 
Gliding  flight,  247. 

Niagara,  2. 
Niners,  173. 
Noctiluca,  72. 

Gnat,   152. 
Gossamer  shower,  267. 
"          spider,  267. 

Number  of  animals,  238. 
"    insects,  238. 

Great  deeps,  104,  108. 
Great  Northern  Diver,  246. 

Oar-fish,  90. 

Great  Salt  Lake,  i. 

Ooze,  112. 

Guillemot's  egg,  54. 

Open  sea,  64. 

Gunnel,  13. 

Otter,  10. 
Oyster-catcher,  n. 

Haemoglobin,  202. 
Harlequin-flies,  203. 
Harvest  mouse,  213. 

Palolo,  59. 
Paper  nautilus,   100. 

Hedgehog,  217. 
Hesperornis,  85. 
Hibernation,  217,  255. 
House-fly,  234. 

Parental   care,   215. 
Pearls,   151. 
Pelagic  animals,  72. 
Pellucid  Limpet,  35. 
Peripatus,  194,  212. 

lanthina,   101. 

Periwinkle,  21. 

Infusorians,  147. 
Instinct,  239. 

Pholas,   24. 
Phosphorescence,  124. 
Piddock,   23. 

Jelly-fishes,  77,  91,  92. 
Jerboa,  206. 

Plankton,  75. 
Polar  bear,  n. 
Pressure  of  deep  sea,  109. 

King-crab,  14. 

Ptarmigan,  219. 
Pterodactyl,   241. 

Lamprey,  172. 

Purse  Sponge,  20. 

Land  crabs,  223. 
Land  plants,  190. 
Limpet,  21. 
Lion,  214. 

Robber-crab,  141,  223. 
Rock-barnacles,  40. 
Running  birds,  243. 

Lobworm,  15. 

Luminescence,  124. 

Sailing  flight,   247. 

Lump-sucker,  56. 

Salamander,  159. 

272 

Salmon,  169. 
Sandhopper,  58. 
Sargasso  Sea,  71. 
Sea-anemones,   38. 
Sea-butterflies,  94. 
Sea-desert,  75. 
Sea-grass,   35. 
Sea-leech,  57. 
Sea-lilies,  121. 
Seals,   10. 
Sea-mat,  16. 
Sea-serpents,  89. 
Sea-skimmer,  86. 
Sea-snakes,   55,   88. 
Sea-spider,   14. 
Sea-squirts,   13. 
Seaweeds,   31. 
Shore,   3. 
Shore-crab,  101. 
Shore-fauna,  10. 
Skate-sucker,  57. 
Skipjack,  230. 
Slipper  Limpet,  27. 
Soaring,   236. 
Soaring  flight,  248. 
Spider's  flight,  268. 
Spiny  Ant-eater,  218. 
Sponges,  17. 
Star-fish,  46. 


INDEX 


Stickleback,  162. 
Stinging  animals,  16. 
Stoat,  220. 
Storm  Petrel,  82. 
Swift,  232. 

Temperature  of  deep  sea,  ziz. 
Tree  animals,  229. 
Tree-lizard,  263. 
Tree-snake,  263. 
Turtles,  87. 

Underground  animals,  226. 

Venus'  Flower  Basket,  123. 
Vulture,  248. 

Wasp,  235. 
Water,  156. 
Water-flea,  95,  147. 
Water  insects,  177. 
Web  of  Life,  149. 
Whale,  77,  100. 
White  animals,  220. 
Wing  of  bats,  253. 
"    birds,  244. 

"      "    flying  dragon,  241. 

"      "    insects,  223. 
Winter  sleep,  2Z7. 


